This isn't an endorsement for Notion, I also dislike it and use other tools. I can see why some do however, it's a solid second brain organizational tool, somewhere to place things "long term" and keep them. It's a less "active" tool, which is also why for some people I think Notion is the wrong solution but for others works great. Think: internal team documents in one central place (less active) vs updating your app's documentation multiple times an hour (more active), the latter of which is not what Notion is good for at all. Also I will say, with their API you can technically hook up whatever databases you have within Notion for use, so it can easily become a place to store your blog notes and use them without copying/pasting. But again, blog notes are rarely changing so you see the pattern here I hope.

I also don't get the notion template hype on gumroad/etsy/producthunt/etc. You can create them yourself within seconds, but that's the nature of the "productivity industry", you get big bucks for the mere idea that your product will make their life easier/faster.