> Zoom made it easy accross ALL operating systems

Many solutions don't require a local software. That's an onboarding hurdle. Zoom's dial-in system also requires host approval, which lead to mayhem across every Zoom call I've been forced to join today. Most importantly, someone inviting me to a Zoom call says something about how they value security.

Zoom's audio quality is better. But it's not irreplaceably better. In terms of UX and reliability, it's been a mixed bag. In terms of security and branding, it's awful.

or is the difference that any other tool runs in the browser (which might be old or locked down), while Zoom childishly just gets admin-privilege to turn the tables in its favour?

Zoom is worse across most operating systems. It is worst of all on MacOS, where it downloads an installer without asking me. I then have to click a link saying that it didn't work, whereupon, it will download the installer again without asking me before finally giving me the option to join the call without installing that buggy app.