Vector indexes vs. full-text search

They answer different questions. Full-text search matches the words people typed; a vector index matches the meaning behind them.

Use full-text search when:

• People search for exact names, SKUs, error codes or quotes.
• You need predictable ranking and easy debugging.
• Your corpus is small enough that keyword recall is already good.

Use a vector index when:

• Queries and documents use different words for the same idea ("refund" vs "money back") 1.
• You're building retrieval for an assistant, where the question is a full sentence.

Most production systems combine both, then re-rank the merged results 2. If you only pick one to start, start with full-text. It is cheaper, and you'll learn which queries fail.