They don’t currently get counted the same as Likes (though there is a feature request for it Reactions count as likes?). I think it would be better if they/some were, as the Likes count does feed into lots of different things.
Though for Trust Levels I don’t think they count as much as you’d think. You only need 1 given and 1 received to get to TL2, and people don’t generally lose that one once they’ve got it as there’s no automatic demotion for it. For TL3s you would need to have given 30 Likes and received 20 over 100 days, also not too significant (and they’re configurable too, if you found it was a blocker [1]).
Reactions aren’t going to be for every community, but it’s nice to have the option if you want it. 
I think having a community that uses the different features is the best way to show new members what’s possible. Nobody really wants to read a forum manual, so having practical demonstrations scattered around is a really good way to surface all the different things that can be done (and ‘used in context’ has some much added value too).
Though some communities are quite happy keeping it simple, and that’s okay as well.
tl3 requires likes givenandtl3 requires likes received) ↩︎