This thread was fun to read, but I think the VC downloads really appeal to certain people and, for them, it's convenient.
Personally, I prefer to own an album, as opposed to buying an mp3 from iTunes. Even if the mp3 was significantly cheaper, it still would rarely be worth it, IMO.
This analogy fits the VC as well -- unless a game is absolutely insanely priced (Dynastic Hero, as Black_Tiger mentioned) -- I just don't feel the trade-off is worth it.
Since I can't "rip" ROMs to VC in the same way you can rip mp3's from a CD album, I would buy a few VC games. I'd rationalize this by saying that I was paying for the convenience of using the VC, or paying a few dollars to play a game that would otherwise cost $$$.
I wasted $50+ on cell phone games over the last two years... I paid for the privilege of playing goofy games on my phone. The VC, in comparison, seems like a much better deal!
Ultimately, of course, a battered TG-16, custard-caked turbopad + loose hucards > VC any day of the week!