When is it useful to use Algolia search?

I have a search function in my app. I have a Gridview with products (retrieved from Firestore) that users can search through.

I can also use the Simple Search from Flutterflow itself, but on the docs page of Simple Search, Flutterflow gives the message: We recommend using a simple search only for the smaller Firestore collection (with limited records). Otherwise, it can be slow and/or expensive. For a more extensive collection, consider using the Algolia search.

What is "limited records"?

So how do I know which one is more convenient? Simple Search or Algolia Search?