Do you know what it is? Maybe it's the fact that you have so many emulators or have so many different Bios or maybe it's the process of setting things up, but there's just thing that is common for everybody. It's the "why" factor. You have the original copy of the game, but you have an emulator for the system to play the game, you have the game working fine on your PS or GBA, but instead you want to play it on the computer; why do you think we like to play games/Roms of games on the PC? NOTE: This is not to discourage anybody from playing Roms, but merely a topic to kind of put things in perspective. And yes, this is pretty random.
Because it makes gaming much more convenient due to functions provided by emulators that can't be done on real consoles. For instance, fast-forwarding (so you can skip through nonsense repetitive crap), data manipulation through cheat-searcher functions, and (perhaps a popular favorite) save states.
Yea, it's the save states that can save your butt. Think about it, you mess up your training (Pokemon thing) and you want to go back, but don't have the tools to fix it, you can just get yourself what you need. Skipping through long cut-scenes is a good one for sure. But man, think of the Control setup you have to do...the keyboard you have to work with. Heck, I'd like to see controllers hooked up to the PC.
Some emulators do allow you to use game controllers. In fact, if you have a Microsoft game controller, you can use Control Panel under Windows which would allow you to remap buttons there. Tedious, but doable.
For nds i simply use my ds+cyclo. for all other systems I use emus on the PC simply because i don't have the systems. I have 2 PS2 controllers hooked up to my PC works like a charm
yes, I bought an adapter on ebay for like $6 shipped. Its something like this. http://cgi.ebay.com/PS2-PS-To-PC-Computer-USB-Dual-Player-Adapter-Convertor_W0QQitemZ250487959351QQcmdZViewItemQQptZVideo_Games_Accessories?hash=item3a523eef37&_trksid=p3286.c0.m14
I may be off the point of this topic but my personal reason I got into emulation was the simple fact of being able to do it, and having consoles do what they were not intended to do e.g. playing super nintendo games on an xbox system and ect. I bought one of those cheap Gamemon USB converter in a clearance rack at wal-mart works well with Game Cube,Xbox,PS1,PS2 or USB controllers.