I'm a bit torn on the subject. Its a way to preserve more obscure games, arcade games and protoypes of games that were never released. So in that sense I appreciate it.
Not really a fan of emulation of current systems or easy to obtain system and games. I guess its fine if you have a PS2 emulator that requires you to have the original game, since Sony isn't really making money off PS2 systems anymore.
I guess if a console is more than around 20 years old, its not really that bad. Buying a NES game these days or emulating the same game makes Nintendo the same amount of money anyway.