Most ROM hacking communities in the English speaking world of any merit/frequented by capable hackers will generally frown upon such a thing.
You face two main problems.
1) Money makes lawyers perk up. ROM hacking is already skirting the edges of what is acceptable under copyright law and as suing me into the poor house gains them a few screwdrivers, some old books and a soldering iron they tend not to bother even going there, not to mention money exchange might enhance some penalties. Some measure of risk is also transferred to the site hosting it all, even more so if they take a cut, act as a escrow or otherwise vet things.
2) The amount of money offered itself. Some company representative runs up breathless to my front door tomorrow asking me to come sort their legacy programming system (they don't tend to teach 6502, 68000, z80 and other old school embedded chips these days and it is rather niche) and hands me a card. "Is that your phone number?", "No, that is what we offer to pay you" tending to be how that one goes. While I was being serious there even if we go to the more realistic day/project rates for a general programmer type setup that is still not a cheap hobby.
Some might do it for some beer money, and in some parts of the world it might even represent something useful (plenty of Asian countries have very cheap cost of living and also very very very good computing abilities -- https://www.theregister.com/2013/03/22/vietnam_kids_google_interview_pass/