Why do not more people choose a matrix server and use a decentralized way of communication instead of committing themselves to this or that app/company?
Because most people they know use WhatsApp/Facebook/Instagram.
I found a server in the list I posted that was hosted by people in my area and funded by donations. I got in touch with them and they even implemented some bridges with that server. Now I am using it with a WhatsApp bridge, feels pretty seamless.
Not sure when you tried it or with which app but you can use it just like an instant messenger. It can do more like discord but this can easily very ignored.
I have heard that once it was a pain to use as a client but since I started using it half a year ago it felt pretty smooth.