Hazel doesn't close tabs because it's 'like a trip down memory lane.' Mozilla says it has some profile and tab group features coming later this year that might help her organize those memories.
Maybe it's just my ADHD, but I can't even imagine managing that many tabs.
In my workflow, I start a project, then keep opening new tabs as I need to look things up, frequently moving tabs between multiple browsers spanning my 32" monitor. So long as I'm working on that problem, I just keep opening new tabs.
Then, when I've finally squared away the section of the project I was working on, I usually just close the browser entirely and start fresh.
Needing to manually sift through the 80+ tabs I chaotically opened in the last hour or so to figure out what's worth keeping? Hell no. That's what browser history is for. It's Etch-a-Sketch time! Shake it clean and start fresh.
Whereas my ADHD has me keeping huge numbers of tabs open (although my record is only ~350) because once it's closed, it's completely gone from my mind. Bookmarks are a burial ground, and history has all the other stuff that I don't need to reference anymore. With tabs, I can go through them and remember why I kept it around, and close it once I've actually done something with it.