I don't know what the meaning of this is. Even people who use those hashtags have no clue what it is. But, when they notice something viral and trending, they tend to use it for engagement.
I just remember this 14 year old incident on Twitter. An abusive word tag was trending that was a regional word, I guess. People are using the tag without even knowing the fact it is abusive. Back then there was not much quality control; X, Y, and Z would trend on the map, and people would be having fun with that.
10 years ago there was a dedicated Twitter trending hashtag website; there were quite a few. We used to blast it affiliate links