As a merchant, it could hypothetically be easier or cheaper to deal with Bitcoin than other currencies online. (For example, note how aggravating/risky PayPal is.)
It's not. Given the volatility of bitcoin you're taking on a lot of currency risk since the value of the bitcoins you just got for your widget can change a lot in a few days. The extra cost of conversion and/or hedging is not worth it.
Especially when you consider all the other problems that bitcoin has.
There are bitcoin payment processors that allow customers to pay in BTC, and deposit the money in the merchant's account as USD immediately, thereby solving this problem (with a price).
I don't know what the state of the art is here, but presumably, that price is going to approach zero, since this is a competitive space, which is not the case with traditional payment processing.
It's not. Given the volatility of bitcoin you're taking on a lot of currency risk since the value of the bitcoins you just got for your widget can change a lot in a few days. The extra cost of conversion and/or hedging is not worth it.
Especially when you consider all the other problems that bitcoin has.