And as much as I dislike Paypal, they offer completely free money transfers (non-purchase related, free for sender & receiver) that are certainly as easy if not easier than purchasing Bitcoin. They also offer very low international transfer rates (0.5% - 2%).
I sell Paypal USD on bitmit so I have some experience with this. Going AUD->USD I seem to get hit with more than that. Nor are my transfers free. The fee depends on where the receiver is registered, but 1% is typical. I make the buyer pay.
Generally your arguments are sound. As a mechanism for doing a fiat transaction Bitcoin is only a winner if you need to stay out of the gaze of the evil eye or you want to transfer a small amount irreversibly. Otherwise Paypal, credit card or bank wire will probably be cheaper, faster and easier than fiat->BTC->fiat. Non-scene merchants who accept Bitcoin are probably inspired by its price rise and don't convert back to fiat.