I've noticed coworkers starting to use them in communication (emails, Teams chats, meeting minutes) so now maybe I see others doing it I feel it is fun and acceptable and might throw some in too. I wouldn't put them in code or EDC or any source documentation but an email sure why not.

I did have a scientist recently write a list of lab best practices and before he wrote the list he had a note "Follow instructions below" and then he had a finger pointing DOWN emoji pointing to the list... my work bestie and I actually screenshotted that and sent it to each other and were giggling about it, because he generally is a serious, smart, straight-laced dude and him putting in a garish down facing bright yellow finger emoji just seemed very silly compared to his personality. But it caught our attention and ensured we both read his list!

I would say the uptick is also partly responsible from people using their phones more often during work communication, if he sent that email from his phone instead of his computer it was easier to throw in an emoji to emphasize his important list.