If I was one of your readers, I'd much rather read on your self-hosted blog (bonus points if there's RSS)... But I'm not. Since I'm neither a reader, nor the one who defines what fun means to you, I'm not sure my—and other commenters'—words should have too much bearing in your decision.

I say, do what makes you (and your readers) happiest. Even if medium is by some measure bad, I'd guess it's "only" about as bad as every other closed-up commercial option—I think they all suck. Look into what you actually care about, though, e.g. privacy, then make your own call.

For what it's worth, I agree with people saying medium is almost inexplicably annoying. I consider myself a patient person most of the time, yet nothing kills my interest in an article faster than seeing websites like medium full of dark-patterned cookie banners and popups and newsletters and signups on the other side of a link.

But maybe we're simply the wrong crowd to ask.