It's a great way to keep an overview on an array of topics. I set them up for a large array of interests of mine, e.g. business (slavelabor, juststart and others), cool PC setups (battestations and unixp0rn), DIY, development, passive income, indoor gardening, cooking, ebikes, streaming tv (Plex, PlexACD, TiviMate).....
If you ever want to see the best ideas in a niche, just sort by > top > this year or all time, and you'll get great ideas and inspiration.
I just laugh when people say Reddit is rubbish, they just don't know how to curate and look properly for the gold on there.
You can also browse multireddits set up by others:
