Adult ADHD: that shit is real, man. I'll try to break it up for you.
I totally need to get my own place for this exact reason.
Rationalize it any way you want. What you're doing is still illegal, and you totally miss out on that warm fuzzy feeling of playing the authentic cart, whether the hardware is authentic or not.
Try before you buy. I'll be the first to admit I have bought many homebrews only because a ROM was released. For example, Drag00n of NintendoAge recently released his Fix-It-Felix Genesis homebrew. I downloaded it, played the first level, and immediately requested a physical copy from him. I may not have nibbled if I hadn't tested the gameplay first. Also oftentimes I'll see an interesting looking game cart at a used game store, I'll drive home, download ROM and/or watch youtube review, and if it's good, drive back to game shop and pray the game is still there.
If you're picky enough, even original hardware can be inaccurate. HD Graphics, late release model 1 Genesis/MD, and a variety of Model 2s/3s don't even sound alike, and certain late models (Mejesco Model 2s for instance) have incompatabilities with 32x, CD, GG, Power Base converter, etc... So if official hardware at times can't get it correct, do you really expect clones/emu to do so? I'll admit modern emulators oftentimes get it better than clones, but nothing is absolutely perfect, not even original hardware. For instance, you get crashes or blinky screens or corrupted graphics on NES. You get distorted audio on certain Genesis revisions. Atari looks like vomit on modern HDTV. Do you really expect emulators to duplicate this and other inconsistensies?
Do it!
