I’ve chosen not to use reactions. And one reason is that Likes are built into Discourse’s mechanisms, whereas reactions are somehow a disconnected extra. IIUC, you don’t get level promotions for reactions, and you may get level demotions if you don’t get likes.
It is true that some people don’t like the heart, and prefer a thumbs-up. And some people like the creativity of choosing the reaction that fits their mood. But I find reactions confusing, so I haven’t enabled it on my forums and I don’t use it here.