Are Federal Jobs worth the effort?

If you are not being referred the issue is with your answers on the questionnaire or you are not making your resume “match” the announcement. If you are getting referred but not interviewed keep plugging away, in my office we normally interview the top 3 to 5 applicants. If you are consistently getting interviewed and not getting selected you might not be focusing your answers on what you can do for the organization. Don’t focus on the past, the panel has that information from your resume. Make your answers future focused.

Short answer: yes, it's worth the effort. I was an Army Civilian for 6 years. As a program manager I had hiring responsibility for two GS positions under my direct supervision: one GS14 and one GS13. Because of my grade and experience in the military and private sector, other supervisors often asked me to evaluate resumes and serve on interview panels.
Here's my best advice about applying for civil service jobs:
-Some jobs are advertised, but applicants are limited. Be sure to read the section in USAJobs that tells who may apply. If you find a job that is limited to a single command, for example TRADOC, then watch for the same job to come back around open to "any current employee or veteran," because they didn't find any suitable applicants with the single-command limitation.
-Tailor each resume you submit in USAJobs to the job description. If the job description asks for 2 years specialized experience as a data administrator, then make sure you resume clearly shows you have the requisite experience. If you don't have the experience, you can apply anyway, but your hiring opportunity will be reduced.
-Show results with responsibilities. This was a pet peeve of mine. We often received resumes that told all the great responsibilities an applicant had, but never showed the results of carrying out those responsibilities. You may be responsible for managing a $10-million IT contract, but if you don't show your ability to provide the required services on time, on budget and on quality, then it isn't worth much. If you say you managed 25 employees, I want to know about retention rate, promotions, awards, etc. for those folks.
-Don't sell yourself short. Some USAJobs applications have an experience survey section. Read the experience questions carefully especially if they were written by a manager in a different service. Translate the questions into terms you are most familiar with and then compare the question to your education and experience. Answer the questions honestly, but don't be afraid to toot your own horn.
-Realize that the most qualified applicant may not get the job.
-Veterans' preference plays a big part in who gets the job. A disabled vet with minimal qualifications will get the job almost every time. Veterans and other civil service employees compete on the same level. Veterans often have a slight edge over "any US Citizen" applicants.

Is it worth it? Advantages to being a civil servant.
-Serving your country
-Doing work in an environment in which you are familiar
-Good benefits package including education benefits and free training, retirement pay, Government equivalent of a 401K, opportunity to buy health insurance, long-term care insurance, life insurance at a good price
-Paycheck shows up every payday and always clears the bank
-Opportunity for raises based on both performance and longevity
-Opportunity for performance-based bonus, and non-monetary awards
-Opportunity to move up to positions of increased responsibility and compensation
-No up-or-out. If you want, you can do the same job well for 20+ years and retire
-It is difficult to get fired

Disadvantages.
-Stuck in a rut. Opportunities to move up may be limited by folks above you who are happy in their position and have no intent to retire soon.
-Moving up may require moving out. Higher grade positions in your area of specialization may only be available if you're willing to relocate.
-Bigger salary on the "outside." Some private sector jobs pay better with better benefits, but often less security, than similar civil service jobs.
-No rewards for creativity. Making change is very difficult in most organizations.
-Office politics. Because it's hard to get fired and people stay in one location and one job for a long time, there's lots of time to play office games. Also, lots of opportunities to file all sorts of complaints if you don't like someone or your supervisor's decisions.

Message me if you'd like more information.

I wouldn't go as far as to say the system is rigged but USAJOBS is a pain in the butt and you have to input things in a specific way to navigate it and get your resume through the hurdles.

I highly recommend you have someone give your resume a once over but it needs to be someone familiar with Federal resumes and USAJOBS.

I was medically retired in 2012, worked as a contractor until I transitioned to a GS position in 2014. Federal employment is good but it isn't for everyone. It may not be the best option for 20+ year Retired Veterans as they would be starting over in regards to retirement. But for somebody with less than 20 and who wants to put that time to a pension it isn't a bad option. The pay is decent and the benefits are good too. But it isn't for everyone. If I were in your position I would talk to leadership and HR to see what is needed in regards to resume and qualifications. It could be a clerical issue holding you back that you never knew about.