Jitsi works reasonably well on PC, but not on mobile.

Moreover, Zoom has documentation on how to use it, and Jitsi has none. (They have the stubs for documentation, but the content itself is largely missing.

One other thing Zoom has going for it: name recognition. In a crowded market, name recognition is more valuable than the tech.

Two or so years ago a friend set up Jitsi and RocketChat on his server because 2 friends and I were using Discord for studying for exams and he wanted to try out an open source alternative. It was so bad that we stopped using it immediately and went back to Discord - three people click on a room link, two end up in the same room, one is in an empty room; people kept dropping out every minute; one shared his screen, and while one person could see it, the other couldn't; some people heard others, some didn't; and the installer on Windows was so bugged that one person couldn't even run the desktop version and had to resort to the browser version which had its own problems.

Maybe this has improved since but I wouldn't use Shitsi again with Discord as an alternative.