Literally a scam
I've had a Minehut server for a while and have decided I wanted to switch to a different server host, so I wanted to download my world to put it on a different server just to realize I can't do it anymore with the free plan. This is anti-competitive behavior, to force people to pay to get their worlds off the platform because they prevent users from switching to a different server host. I had to use a world downloader to get it off. I would recommend to stay away from it and use self hosted servers instead if you wanna just play with friends. Running a public server with a free host is probably a bad idea anyway.