[near]

MAME follows the internal database approach to emulation. The primary issue with this approach is that it does not support homebrew, fan translations, and ROM hacks. If you modify games, checksum lookups fail. For a ROM hack, you could still boot something where the original was in the database by manually specifying the name and accepting the warning (which is fine), but for a new unlicensed / homebrew title, you could only maybe possibly boot it by faking being another very similar game, which feels quite wrong.

I'm not saying the MAME approach is wrong: every approach has its pros and cons, regrettably.