I love emoji. It's like you say: it can give written text an obvious nuance which makes sure something does't come across the wrong way. Just add a 😉, or a 😛 and people know not to take what you say too serious.
It's a shame I always have to go and look up the codes when i'musing my laptop. It's so much easier to implement them when using your phone.

I use the non-smiley ones mostly to make something stand out, like the 🌺 for the garden challenge, the 💡 to mark something important or a 🏆 in a contest title.

It shouldn't be overdone, though. I've seen posts with so any emojis in it that I did not have a single idea what the post was about, lol.

I think you never have enough emojis... Often I'm looking for one, and then it appears it simply does not exist...

However, it needs to be obvious for everyone where an emoji stands for. I use the upside down smiley pretty often on Discord. Not so long ago, one of my fellow @teampossible members asked about the meaning of the smiley. It appeared everyone had his own interpretation, and on top of that, it was hard to explain what I meant by using it.