It definitely has a lot of potential for gaming, look at the unreal engine port. Even if that's all it really ends up being, that is still a pretty big deal.
I've been wanting to use it for some b2b applications, or maybe for some reports/charts. Just in places where it makes sense to need that power, but you'd want it in a browser.
Actually I'm really excited about wasm and WebGL inside of the browser. One build target to rule them all. But we're still far, far away from utopia.
Unreal and Unity web builds are not production-ready yet. The cross compilation can be brittle, compile time is huge, the resulting assemblies are large and memory consumption is just too high.
This leads to many, many problems, which are hard to diagnose. Getting games to work on mobile browsers consistently is nearly impossible. For example, last time I checked, Chrome on Android disables WebGL by default and limits memory to 64mb.
Unity is working on "Unity Tiny", but it's in alpha state. Frameworks like Three.js are better suited, but more barebones. Still a long way to go...
I've been wanting to use it for some b2b applications, or maybe for some reports/charts. Just in places where it makes sense to need that power, but you'd want it in a browser.