If I recall correctly, it wasn't about appending an emoji to the end of your comment like you just did, but rather about the type of comments that would be 50% or more emojis, that for some reason are very prolific on the Internet.
And I would say there were two good reasons for this. First, these comments rarely conveyed much meaning, the emojis were used to exaggerate the emotional message, but little else.
The second (and more serious one) was the decline in English proficiency among native speakers (especially youth) that was ascribed to use of emojis and emoticons.
Google commissioned a study back in 2018 that showed, that most adults are not confident in their own spelling, and blame the emojis for it.
If I see a comment with an emoji or two, I could care less. If I see a comment that is just agreement and emojis, I downvote the hell out of it.
Just upvote and move on. Don't clutter up comments with useless emojis. That just suppresses relevant discussion. It's as useless and dumb as the comments that simply say "This."
That's not to say I'm downvoting due to emojis, but rather due to irrelevant discussion. But I will admit if I see a comment that is filled with them (but still has relevant discussion) I downvote because I'd rather not have comments devolve into FB mom quality emoji-laden garbage.
I could understand it for those who spam emojis after every other word, or write entire messages in emojis (not counting single emoji responses). That is annoying and migraine inducing to read.
But adding something to convey how the text was meant to be read sure helps alleve some ambiguity of not having a face to face interaction.