Honestly, the nice thing about reactions is how you can pretty quickly get a general view of what people think of a msg, too many reactions and suddenly that's not as easy to see.
It's also nice to see something that isn't purely a straight-up thumbs up or down, the faces available do let you convey a pretty wide range of emotion.
If the reactions can't quite convey how I feel about a post then that's the point where I'd probably just reply to the post anyway, those emotions are just too niche to justify a reaction emoji.
Would like to see a confused reaction

for those times when someone posts something that's difficult to interpret which I've seen happen a bit. Probably a couple of other emojis that might also work super well as reactions but I haven't been able to think of any