quick question - can a tsvector not be repurposed to do this exact same thing. i know tsvector is text search. but the advantage is that "similarity" semantics

quick question - can a tsvector not be repurposed to do this exact same thing. i know tsvector is text search. but the advantage is that "similarity" semantics kick in with tsvector - with things like rankings, relevance, etc. so i think we can do trigram matching (i could be wrong..been a while since i did this) while pgvector seems to be doing cosine distance matching. im not sure which is better, but tsvector will support the popular RUM plugin for cosine similarity. any thoughts here ?