For me it has to do with this
- I want a feed that updates based on my subscription
- That subscription content could be anything, blog posts, updates on a Wikipedia page (to keep up to date with a news story that is out of the limelight), or get updated with a XKCD comic
RSS meets both these, dead simple. It's also low in data usage, but it's for those reasons that I recently started using RSS after leaving it years ago.
P.S. I believe some blame goes toward "fragmentation", i.e. we still need to check a couple of websites for something new. RSS solves that by bringing all that into one place