I have not hosted a Matrix instance before, but I have read quite a bit about it and talked to a few people who do and have. Is it worth the effort? In many cases, it seems not to be. Also it depends on how much effort you think is too much. If installing and running a server for you is easy, then it could be worth it. If you know that your server won’t run out of resources, then it is probably worth it.

Matrix is known to be resource-heavy, and it will need an infinitely-growing amount of storage unless you can figure out some way to reset storage. Otherwise, you are most likely to need to look for a way to slow the rate at which the data grows. This could mean things like turning off federation (but this makes it less useful), or strictly limiting how many users your server can have. (Only you? That might be alright.)

For every user on your server who joins a room, your server must keep an entire copy of the room since it was created. Some of the data can be thrown out, but a lot of it can’t. To get back the space I believe you would have to part from the room and make sure no one else in your server is joined to it, then I think it would be automatically pruned. So you could, for example, “roll” your rooms by using them for a time, then quitting them and replacing them with brand new ones. (Although if I’m wrong about this, I hope someone will correct me.)

I used to be on a nice federated Matrix server that was public and being run by an ISP, so I thought it would be very dependable. The server worked when it had a small, fast disk (SSD probably). That disk ran out of space quickly, and was replaced by a slow, large disk. Because the new disk was slow, the service crawled to a halt. I then had to migrate back to matrix.org. Disroot is another example; it was a popular federated server, and they were forced to abandon it.

I actually don’t see any reason not to use matrix.org unless you just want the experience or know-how. As a hobby, if running a Matrix server brings you joy then absolutely do it.

Personally, what I do is run an XMPP server, and I found it totally to be worth it. Having that also makes bothering to set up Matrix seem like less worth the effort. (But then, why not both?) People can run small XMPP servers that use a miniscule amount of resources. I just checked, and my ejabberd server, which hosts ~7 people and a couple active group chats, is taking up all of 21 megabytes. (I couldn’t believe it so I had to check it twice.) It is configured to store all messages and uploads for 30 days, and it’s using less storage than it was a couple months ago. (Last time I checked it was more like 40 megs.) Can Matrix do that?