I`m certainly no expert as Iv`e only been shooting 8/9 months so this is my experience thus far...
Having researched Full frame v ASP-C cameras before purchasing my Nikon D500 I quickly came to the conclusion that as much as I would love a Full frame camera the cost to me was simply way beyond my budget so I decided that in order to get some sort of half decent Photos with a camera that was fairly good at the job and not as expensive I would have no choice than to buy an ASP-C .. Obviously there were limitations - there was also Pluses and negatives to going for ASP-C over Full frame .. As it turned out the Nikon D500 ASP-C was a great choice
Full frame meant Huge file sizes given the 45.7 MP sensor of the D850 or similar full frame camera , that would also have meant a very large upgrade on my PC/Laptop as my laptop would never have handled that amount of information so that was a definite non starter ...
ASP-C was a great compromise with smaller file size, cheaper camera, cheaper Lenses, and no PC upgrade making it a no brainer So, for me it was a nice way to dip my toe into the world of hobbyist/enthusiast photography at a price that I could afford .. also from my findings it was highly recommended in my case to opt for ASP-C to begin with until I developed some skills/technic .... For me its been a great learning curve , I can take fairly decent photos of BIF ,some scenery , family etc etc ..
The obvious next step for me will be an upgrade to Full frame either DSLR or Mirrorless -(DSLR V Mirrorless thats another debate on its own) so in a nut shell I`d say the camera manufacturers have got it spot on with the affordability of ASP-C for the beginner/hobbyist/enthusiast and a great way to entice them into the world of Full Frame - Do I really need a Full Frame camera at the moment "Hell No" ..would I like a Full Frame ""Hell YEAH"" The only thing that keeps me from the Full Frame market is "Cost" ..if it weren`t for the expense of it all I would already have bought one ...
Harry.G