No, I meant exactly what I said. It has nothing at all to do with the computer’s form factor, only the power source in use.
bsnes (or higan these days, I guess) is a very accurate SNES emulator, and thus needs a lot more CPU power. It should run just fine on a 2011 computer, I’d imagine (haven’t tried it lately, myself). However, more CPU power requires more electric power. Normally, having all the accuracy you can get is just better (except your machine will run hotter and maybe there is something to be said for not unnecessarily contributing to the environmental impact of power plants). But if you’re on a battery, then not only will the more accurate emulator eat through battery power quickly, possibly ending your gaming session prematurely, you may (or may not!) find it doesn’t perform very well: graphics and CPU in general are throttled on battery power, and there is pretty much nothing you can or would even want to do about that. Since snes9x is sufficient for most SNES emulation and can run splendidly on some fairly weak systems, it’s a better choice for low-power situations.
Saves (not save states! SRM files.) are transferrable between SNES emulators because they’re just the raw data that the SNES game would have saved. They might need some renaming or moving, but switching between emulators is not really a hassle as long as you’re using in-game saves.