First, history shows a general trend towards fewer currencies (every state and damn near every bank in the US had their own, the Euro), though I appreciate you semi-acknowledging the commodity traded "as" currency bit. I think the lack of stability is the primary reason people are staying away from bitcoins, and a huge reason not to accept them.

Automatic conversion at least eliminates the concern of value decrease, which I think is a real concern. Of course the economic value of the donation does not matter to the donor after it has left his hands. But, if I donated a bunch of cymbals and saxophones to a high school band, I'd be pretty bummed if they got destroyed in transit, thus decreasing the emotional value of the donation to me. Similarly, if I donated 2 bitcoins, only to find that, before you were able to withdraw them, their value went from $1,600 to $200, I'd be disappointed that I didn't help as much as I wanted to. Economically, I'm still out the $1,600 either way, but dammit, if I'd used a credit card or written a check, at least the whole $1,600 would have ended up where I wanted it to! Bitcoin glitches
more bitcoin security issues
bitcoin is not a currency explained