Gossip does not use pocket.  I built things in this order:   nostr-types, gossip, chorus, pocket.  I backported pocket into chorus so now chorus uses pocket.  But pocket only has a very simple interface, just enough for a relay, not nearly good enough for a client to use.  That may change but I'm not working on such.

Gossip uses it's own LMDB storage which is a tad less efficient but much more fully fleshed out for client usage.

Also Gossip isn't interacting with it's local database in the same manner it would with a relay.  I know that some other clients create a local relay style cache, but that is not what we are doing. We have a custom internal API that is nothing like querying a remote relay.