It is so nice when technology works.
Got myself some train tickets (I like trains! 🚆 ), confirmation went to my e-mail address which I self-host using @yunohost.
I read the e-mail in the Mail app on my @nextcloud instance (on the same yunohost server), and of course it helpfully suggested I add the travel dates and relevant info into my Nextcloud calendar.
We *can* have nice things. Anyone who says #FLOSS cannot be user-friendly is lying through their teeth.