Of course, but more reduced: 1. When using nostr regularly without bostr, You are connecting 5-10 relays (or more), Which consume more bandwidth than how it is on single relay. For example, Each 10 relays consume 10 MB of bandwidth. If multiplied by 10 (amount of connected relays), You are consuming 100 MB in total. 2. Bostr solves this by taking the entire bandwidth on server side while the client gets reduced bandwidth. This is useful for users that's using monitored broadband (mobile) data.