Dunno if it's a generational thing or what, but I check my email like maybe once a day sometimes I can go 2-3 days without looking at it. It's just a place where Stuff gathers and I go through it when I Get around to it. Can't even remember when I used email to actually communicate with a non-business entity outside of work.

WhatsApp messages I get immediately.

Surely checking once every three days is frequent enough to see an invite for a meetup that happens once every eight to ten weeks?