Definitely no.
If you want to wreak havoc, just go on and install Mimic. Thatʼs pure evil, and the “correct” way to abuse Unicode. All of a sudden your code stops working, even though it looks OK. With Emojis, however, you canʼt really be sure; it either works or not. It either looks good, or your editor displays little squares (good luck debugging int ⬜ = ⬜ + ⬜…)
So please, donʼt even think about it. Commit messages: maybe (although iʼm against it). Source code: definitely not.