While this might be great for new users, who don't want to bother with the system, you don't have any control over your own private keys and this is fatal. Yes, they say, the Bitcoins are insured, but finding an excuse won't be too hard for them. From the last goxxing we should've learned that without being in the full possession, the loose of Bitcoins through the business failing is inevitably higher.

Also, why bother with Bitcoin if you don't want to appreciate any of it's real benefits (decentralization, pseudonymous, etc), but just jump in because it's either hip or soemthing alike. Fast transaction times are also possible with PayPal