Most of the time it's a non-issue - upgrades are automatic and without issue, but when there's something up with the server, it was useful to have a "your certificate should have been renewed by now" notification to go check it out.
My website had some sort of possibly related certificate hiccup last night. I couldn't remember if I had manually set it up through LE/certbot (I did this for a work domain a few years back, so maybe had it confused with that), and had a discouraging poke around before retiring (to bed). Anyway this morning it's back up, apparently all thanks to my benevolent, taciturn, and very difficult to contact hosting provider.
They just sent me another reminder that they won't be reminding me anymore. I used to use certbot when I had an owncloud server. Then I switched to Nextcloud with a snap and it's sort of automagical. I didn't know it would do that so there's all kinds of left over bits and pieces of not-snap letsencrypt and certbot lying around that I must get rid of one day.
ISTR having done this previously by adding A records to the domain DNS to validate, but my personal domain registrar (GD, who else) has custom DNS servers set by my hosting provider, so I can't edit the DNS. Anyway it's been so long I'd have to read through it again, and it's probably all changed.