You'd have to update the embedding every time the data used to generate it changes. For example, if you had an embedding for user profiles and they updated their bio, you would want to make a new embedding.

I don't expect to have to change the embeddings for each icon all that often, so storing them seemed like a good choice. However, you probably don't need to cache the embedding for each search query since there will be long-tail ones that don't change that much.

The reason to use pgvector over blobs is if you want to use the distance functions in your queries.