It does work. Still i would not recommend official multiplayer plugin usage for a real time shooter. As far as for smooth experience in such games latency should be not higher than ~100 ms, which is hard to achieve with this kind of an architecture (direct p2p with NAT traversal).
Best solution i found so far is a WebSockets and Node.JS backend.
In this case you are fully responsible on hosting it where you want, maintaining it as you want, developing server logic as you want. Which is relativly hard, but gives you 100% of control over you product.
In case if you don't want to dive into it - there is a less complicated option - Photon Engine, still using it you are relying entirely on their services availability. So if they have lags - you have lags, and there is barely anything you can do about it.
If it's a really small game with no competition, or you can afford to have 100 ms desync you can actually go with official plugin, it does work perfectly if really low latency is not required.