A highly specialized Web app doesn’t need to support more than one browser. If you’re a Firefox user, consider it as though it said “please download the Spotify app to use our service on your machine.”
Right, and I'm saying I fundamentally disagree with this vendor-locking approach. Qt doesn't lock me into a particular environment and is cross-platform. It's a view framework, not an entire browser. Huge difference.
I agree also its an early iteration of the product. I think you would prefer to get a working version out there earlier and get feedback about the product rather than wait a month and get it right in every browser.