In the old days, people said you shouldn't write crypto in JavaScript because it was somehow insecure. Have those concerns gone away with WebAssembly and https everywhere?
However on the bright side performance.now() has a much worse resolution on most browsers, making timing attacks harder.
Definitely not for browsers as the execution environment, at least browsers running extensions.
Nowadays, it's a lot harder to get past browser security and people run all sorts of applications in browsers such as banking, business critical SAAS, email, etc. So, perfectly fine to include some crypto in that and probably not optional to do so for a lot of applications.
What's still true is that you should not be rolling your own crypto libraries and instead use libraries from reputable sources that have been scrutinized by people that know what they are doing. That's true whether you use javascript, C or whatever. And of course with web assembly you can just compile those libraries and use them in a browser sandbox.