I built my own note taking ios app a little while back and adding embeddings to my existing fulltext search functionality was 1) surprisingly easy and 2) way more powerful than I initially expected.
I knew it would work for things like if I search for "dog" I'll also get notes that say "canine", but I didn't originally realize until I played around with it that if I search for something like "pets I might like" I'll get all kinds of notes I've taken regarding various animals with positive sentiment.
It was the first big aha moment for me.
At the time I found Supabase's PR for their DocsGPT really helpful for example code: https://github.com/supabase/supabase/pull/12056