I like having string encoding that explicitly tells me 'emoji of an old man walking his rhinoceros'. Its so much nicer to work with than having to write a custom parser for each source, like if I needed to parse github's :boat: syntax and worry about all the magic quoting rules. The world isn't going to go back so ASCII smilies. That :boat: has :bon-voyage:.
I'm not sure why people get so worked up about it? If you don't need them, you don't implement them. If you do need them, it makes things better.
Next up, how identical emoji in different cultures can lead to miscommunication. Or identical words for that matter.