It sounds like a cool idea, but the first thing I thought when I read the part about not having to be concerned about expressing sarcasm, worry etc. was the whole Bitchy Resting Face trope. After all, with a lot of people one can't tell if they're being sarcastic when you're standing right in front of them. Or happiness: there's always the people whose version of a cheer is to nod slightly and perhaps say "Good" out loud.
Emoticons and emojis can be a blessing to the non-extroverted, quiet, Type B sorts.