I don't know if it "hurts" or "helps" a channel using emojis, but their usefulness in terms of serch probably depends on how the code of the emoji is read.
I've done a little bit of reserach into the code style, as different apps and websites display emojis differantly. There's "emoji code" there's "unicode" there's "CLDR Short Name" there's other codes, like U+1F600 is apparently code fro "smily face" "Unicode CLDR data" and then of course, if you're in YouTube chat, certain emjois are summoned by codes like : joy : which will show up as
heck, I don''t know if that will show the graphic, or the text code
So with all that being said, I'm not sure how much those codes impact on a video's serchability and ranking etc.
I've used them, but not very often and I probably wouldn't worry about using them in titles because overuse of emoji's can not only look spammy, but they can look childish and give your video the wrong impression before it's even clicked.