Even if you have Coinbase turning BTC -> USD automatically, there are still issues. Here's just one:
I purchase something on Overstock for 0.5 BTC. The item has an issue, and I want a refund. In the meantime, the price of BTC/USD has fluctuated 20%. What happens?
This question is not insurmountable, obviously. But there are tons of edge cases that need to be thought of and dealt with.
I don't see tons of edge cases. Any current logic tied to your existing payment processor must be reimplemented to handle another one as well, in this case, Coinbase. Internally, everything is dollars. Coinbase handles Bitcoin for you.
This may be good PR for App.net, but it's bad PR for Bitcoin and Coinbase if the idea that accepting Bitcoin is complicated spreads. It isn't. Using Coinbase is as easy as using Authorize.net, unless you make things hard for yourself by pricing things in Bitcoin.
I purchase something on Overstock for 0.5 BTC. The item has an issue, and I want a refund. In the meantime, the price of BTC/USD has fluctuated 20%. What happens?
This question is not insurmountable, obviously. But there are tons of edge cases that need to be thought of and dealt with.