> if you care about WebAssembly performance, use Firefox

Unless you have customers or want them, because Firefox's market share is generally too small to base your entire business around.

I think it was meant that YOU, as a single human being, should use firefox

In the old days there were websites using flash or silverlight and they had a screen "in order to use this you must use flash" and for some reason, people did download and install flash so that they could watch the cat videos or whatever.

The big difference is that without them they would see a broken square, with Chrome or Safari they would still see it, just a bit slower.