I didn't use the GPT3 autocomplete API in the end (though I did play around with it) but did use the embeddings API (which I believe is still considered part of the "GPT3" model, but I could be wrong!).
I totally could! I think each use case should dictate which model you should use, in my case I was not super cost or latency sensitive since it was a small dataset and I cared more about accuracy. But I'm planning on using something like https://huggingface.co/sentence-transformers/all-MiniLM-L6-v... for my next project where latency and cost will matter more :)
I have a lot of thoughts around that last question! The Supabase article came out way after I implemented this (August of last year) so I didn't even think to do that, not sure if it was even supported back then, but I'd probably reach for that if I was re-doing the project to reduce the number of systems I needed. I think the power of having the vector search done in the same DB as the rest of the data is that sometimes you may want to have structured filtering before the semantic/vector ranking (ie. only select user N's items and rank by similarity to <query>) which is trickier to do in Pinecone. They support metadata filtering but it feels like an after thought. For the project I'm working on now (https://pinched.io) , we'd like to filter on certain parameters as well as rank by relevance, so I'm going to explore combining structured querying with semantic search (ie. pgvector or something similar on DuckDB if it adds support for this).