As I understand it, VA benefits hinge on whether or not you are returned the same as they found you, not your ability to work.
That is the basic premise. You were assumed to be completely healthy when you passed your entrance physical and now you've had some wear and tear related to the military along the way.
The big problem as it pertains to follow on careers like aviation is that the people who are there to 'help' the veterans do not understand the implications of some conditions. Their stated goal is to get the veteran the most compensation for their service. They don't know what conditions are disqualifying or not.
Whenever a service member (officer or enlisted) leaves active duty, they are mandated to attend a transition training course. Covers things like using GI Bill benefits, resume and job application prep and during the process you get visited by the DAV (Disabled American Veterans - Non-profit folks who advocate for vets) who go over the VA process and how to file your claim.
The claim involves taking your complete medical record to the DAV rep and they review its entirety looking for any possible condition that could result in compensation. They'll flag stuff like a knee injury 15 years ago or Medical gave you vitamin-M (Motrin) for back pain back in 2015 so they flag those for the VA to investigate. The VA then determines whether or not the claim warrants compensation. The DAV bombards the system with every possible thing wrong with you to achieve the highest disability rating for the veteran. That is their goal.
But, if YOU, the member, aren't careful (or are someone trying to milk the system) then you can get flagged for stuff that could preclude you from flying. When the DAV submitted my claim, I found they had flagged stuff I never knew I had. In one case, they put down that I had been treated for some kind of chest pain. I went back and couldn't even find anything remotely related in my record, so I have no idea what they based that on. When I had my appointment at the VA, I made sure the Doc noted that it was not a legitimate claim and only addressed the issues that I felt were legit.
The kicker is that in order to find that out and head it off at the pass, I personally had to look up the codes that the DAV had put on my claim. I did that because I was thinking FAA medical complications, but how many others are that diligent? I'm sure the DAV rep thought they were 'helping' me.
Others may disagree, but from my own experience, I think the VA does a decent job of determining whether or not the conditions are legitimate for the most part, but where I think it gets sticky is mental health stuff like PTSD. DAV rep sees that a pilot flew combat missions and flags it for PTSD. Pilot seeking to max out their claim says all the right things for the VA to validate the claim and they get paid.....but then when they realize that PTSD is disqualifying for that lucrative airline career.......well then the whole integrity test comes into question on the MedXpress form....
Funny side note on Disability Claims: My AME specializes in Aviation Medicals and evaluating VA disability claims. Has a 2.5 out of 5 star reviews on various internet review sites and that is because 50% of the reviews are 5 stars and the other 50% are 1 star. When you read the reviews, it makes a little sense - the pilots all give her 5 stars. The haters are all people bitching that she didn't support their disability claim!