I believe they serve different purposes. nostr.wine would be your standard outbox relay where all of your notes go. filter.nostr.wine on the other hand is essentially a web of trust relay, pulling in content from your follows and their follows and allows you to broadcast to several other relays too. 

 Derek my dude that’s a huge help, thanks! I vaguely recall additional or different layers of spam filtration but as far as the difference between content consumption and creation, makes perfect sense