You're right. It was barely useful for me since I always have the phone face-up, to see who's calling. Although I really like the stock Android experience on the Phone (1), it's fast and smooth.
One thing I just noticed is the privacy policy. It proxies the data to their server and can collect analytics. I do understand it's to circumvent CORS, but still we've to keep that in mind.
They're actually not redirecting now as traffic has subsided. But as I remember, they added a 301 permanent redirect instead of 302 and I immediately thought that's a bad idea. Probably that's why you're still getting redirected to the stream.
Should I disable windows firewall if I use this? It wasn't clear from their docs whether I should.