For sure, I personally use pgvector myself but I also don't have millions and millions of rows. I haven't messed with anything other than Pinecone so I can't speak to those services, but there's a big difference than a vector db for your own personal use and a chat app/search on a db with millions of users convos and docs, not sure how well these managed vector DB platforms scale, but you probably need the db guy anyways when you're using vectors at scale. Atleast I would.