The use of a Materialized View here is clever, but it means that every time you add a new row you have to refresh the view. For an app that accepts user-generated content, this would be very frequent since you wouldn't want users to create content and then test the search and not find it.
I don't know how optimized "refresh materialized view" is, but making this efficient is easy if you do materialized views the "old school" way, with triggers (create a table instead of a materialized view; create triggers to update based on individual rows, and a function to refresh the whole view).
