Tangential, when you mentioned "Full-text (BM25) and semantic (pgvector) search", what are the significant benefits of the latter? I used to think of BM25 index

Tangential, when you mentioned "Full-text (BM25) and semantic (pgvector) search", what are the significant benefits of the latter? I used to think of BM25 indexes as vectors of documents, which support search, "more like this" etc.