Great feedback @DEV_Scribbles but it is admittedly one more step away from a clean interface - and collapsing also still leaves behind a trigger.
And as to the fact that it is supported on preview mode and why isn’t that sufficient? I would argue (again design aesthetics and usability) that it is in Edit mode that the need for clean space is the most important. It is why iaWriter was successful with its super-clean writer focus mode.
There is something beautiful about starting a new card with it being completely a blank page, ready for filling. Having to see a computer-ese YAML header with metadata fields for every card is a quick mind sucker for creativity.
Of course, just my thoughts on the matter and putting it out there. 
Welcome the discussion!