Reusable blocks have a long history now. The started as "saved blocks" and went through some renaming iterations until we settled on "reusable blocks". This worked alright at the beginning, but with the introduction of patterns its meaning has started to become more fuzzy and confusing (see related comment). In the end, patterns are also reusable pieces of design.

Given the nature of these blocks is to have content in sync wherever it's displayed — edit once; update everywhere — I propose we change the name in the UI to "Synced Blocks" and adjust the block description a little bit to clarify that.