I’ve also used Matrix and Fluffychat, and it works fine, but even just considering the electricity consumption of the server compared to something like XMPP, it seems wasteful unless there is a real need to use Matrix-exclusive features or clients. Of course some people on older/low-end hardware might also experience issues based on the resources that Matrix requires. I have nothing against it, but I question whether it should be considered the default when there are in fact other options available and have been for years.