I think what is important is to have it configurable.
For example, in ProxySQL Query Cache you can choose which query to cache and which query not to cache.
And some times it also makes sense to cache query that MySQL QC wouldn't cache. For example, once I saw an application running `SELECT NOW()` hundreds times per second (across multiple clients). Caching `SELECT NOW()` for 500ms on the client side would have reduced a lot of unnecessary network round trip.
Author of ProxySQL here.