What alternative is there that has: screen sharing, voice calls, all your friends across every community in one DM list, meaning that you can make group chats across communities?
You can be stubborn and rely on a platform your audience/community probably doesn’t want to use and have a very steep uphill battle to success. Or you can take a risk and rely on a platform you don’t own and have a (somewhat) less steep uphill battle to success.
If the platform is good enough and the benefits of using it are significant enough, people are going to take the risk. See: App Store development, selling on Amazon instead of your own e-commerce store, etc.