Doesn't really matter if the client is open source does it?
The compiler is the interesting part here, crowd funding a third party proprietary service is a bit odd.
I'm not sure anyone would really trust code being built on a third party website without transparency. Nothing is to stop you from injecting shady code, etc.
Anyway, my two cents: the compiler is interesting but the service is not. Best of luck.
They are, but still very much in flux, tooling support is lacking at the moment and since that is likely the number one feature people are going to try out immediately so I left it out for now.