That is somewhat correct, but the catch is the server still sends you the unwanted posts. With blocking them the server / the instance you are on is the filter you want. 1. Faster loading speed ( minimal like few milliseconds ) 2. There is not the possibility that your feed is literally empty or just 1-2 posts ( because it would be somewhat resource heavy to fix the filtered posts in the frontend without fetching like the next 2 pages. )