I think emojis are the new overused punctuation. So many options when you start to add that second and third exclamation point... now the sky is the limit :) I am a bit formal in business communication. Younger people don't draw the line between business and social interactions as sharply. To answer your question, overuse of punctuation or even gasp emojis in business communication offends me.
I'm gasping here too - emojis in business communication? Oh dear me no. I hadn't thought of emojis as punctuation but you're right, they're being used that way. I've been trying to learn them because 'everyone's doing it' but they feel very awkward to me. I might be better off staying old fashioned.