I might click favourite, but not boost. My reasons for when I do what is very different. And I might not want to boost everything I favourite.

On twitter I used Like as an acknowledgement like a thumbs up & here I may use Favourite for the same reason. What other reason would there be? To encourage people to keep posting things that you don't want to Boost?

Fedi is very different to Twitter. The goal is not to post things just to haunt boosts.

I fav I use like a thumbs up / I care / I see you etc depending on the post. And not everything needs to be boosted. (Hint, boosting all the things fet spammy in people's feeds).

Boost is more like "I want everyone to see this" / this is really important.

Boosts is also not the only way for people to be aware of posts, while it might be somewhat visible, it is also not the only way.

I am not a social person, but they don't have Asocial Media.
My goal is as Cassandra, to spread what I see as blindingly obvious to people who can't see it.
I like boosts. Being boosted in the wilderness, void.
I don't call it preaching but I'm sure others do.