Yes, there are two reasons nobody wants to use BitBay to buy/sell something:
1. Horrible UI.
2. No one in his right mind will download the blockchain or try to learn what's "bootstrap". I mean common people, byers, not crypto enthusiasts.
I think once the api is done and we get some websites and mobile version then more mainstream people will adopt it.
ebay resellers will be able to make money just from the fees especially over seas with the auto added on evil ebay fees and taxes now.
If that gets done before the peg then we can look at pegging much higher to start.
The possibilities are endless but there is only so much one person can do.
Bitbay eventually needs sidechains to enable other teams to plugin and fund raise then build on top of the core. Although even without this it can rival the top 10 projects.