If they were going for the commodore aesthetic, 1) may be don't call it workbench OS to confuse people and 2) the numpad (if it was called that then) is on the wrong side. It was on the right on the C64 and the amiga alike like it was.

Would this benefit left handed users? I know people call for reversing mouse buttons and mouse hands but I've never seen an ask for flipping the position of the numpad.

They don't have to replicate everything exactly as it was in the original machines to give the right vibe. It's similar, not a retrocomputing reproduction. Also Amiga was made by Commodore - it's in the same family. I don't expect anyone to be confused by the workbench naming though - it's a weird name, but why would anyone stick the actual workbench os on a multi-GB machine?