I'm not a fan of digital games, but I would probably buy a couple to show support for the NGPC, if it was done right. I'm not happy with any NGPC emulators on other platforms, so I worry about how this kind of thing would turn out.
I would only buy if there was strict DRM, possibly having to enter a randomly generated password that has to be be decoded off of a cardboard wheel everytime I want to play...
I definitely would be pretty happy to see games ported over to VC. As much as I enjoy the actual NGPC hardware, it's nice being able to carry a ton of games saved onto a SD card.
I'd buy them, well most of them anyway, assuming the price was right. If they were priced in line with what Nintendo charge for gameboy games then I'd be fine with that.
I would definitely get some of the more rare/expensive titles I haven't been able to purchase like Cotton. I wouldn't get every single release, but I'd get a few of the fighters as well just so I could play without having to worry about a light source.