Perfect timing - I just created a comment block (only shows in Dashboard) and I wanted a way to clearly show that it was a comment block (apart from the colouring). I copied some CSS from this plugin to add 'comment' in the top right of the block.

I do see a brilliant use case - distinguishing which column block is in use when you have plugins that provide additional column blocks. It's often hard to know whether you are using a core block or an identically named one from a plugin.