Not really. Video game servers definitely don't want session oriented protocols, and don't really care about dropped packet. Lost the packet with the player position? It comes at a regular interval, so we'll get it anyways, and more up to date! All they care about is the best latency possible. As for the non-time sensitive stuff in games (scoreboard, nicknames, etc), there is no real benefit there either. It's not time sensitive, the connection get opened once at the start and that's it.

Where QUIC really shines if for fast connections and many streams, ie the web where a page will need 500 resources spread across 100 hosts. In this case session establishment speed and parallel streams are paramount.

Not a whole lot, but the connection identifier will probably make it much more seamless when your phone switches from wifi to mobile networks. Right now, that's somewhat disruptive; with QUIC, you might not even notice.

For games running on the browser absolutely yes. They are all currently on tcp and being able to switch to udp is huge.