Because most doctor visits right now are “telehealth” visits and as a patient you have zero say as to what platform your doctor chooses to use.
Just say "teams doesn't work well on my computer, it's very poorly made. Can we use jitsimeet? It's much easier for me." and them drop them a jitsi link without waiting for their response.
Teams is the official video chat at my company, I've been successfully ignoring that for more than 2 months now. At this stage, jitsi usage is starting to spread to other teams.