One of the factors is how users phrase their queries. On some level people are used to full text search but semantic shines when they ask literal questions with terminology that may not match the answer.
Exactly. Full text paradigm has it's own pros and I believe we need those tools in the new vector search to take full advantage. I am planning to add keywords feature where if a user enters something in "quotes", the would need to be in the shown results. Just like you can do with a google search.