I imagine Dreams is kind of similar to Mario Maker in a way, but less popular. Dreams however has a lot more variety when it comes to creation. With Mario Maker, you are limited to just level design, but with Dreams, you have a lot more options. You can create entire games from scratch with level design, sound design, custom elements/models. It also isn't just games, you can make animations too and some of it is really impressive. It's still user created content so a sizeable amount of stuff will be kind of trash, but I would say a good chunk is quality content. I played a Kaiju destruction sim, watched a really cool animation about like a bird robot thing, and played a bit of the Dream dev teams fully blown game they made in the editor. Games like this and Mario Maker are the things that end up inspiring young people and others to become creators like level designers, artists, game devs, etc. It's kind of cool actually.