Mistwell
Crusty Old Meatwad
Welcome to the abstract nature of 5E rules. The same issues come up when a caster is blind and casting spells. I believe they are written that way to allow the widest interpretation possible by the table. But that will place an additional burden on the DM to handle more undefined areas of the game. All I can advise is think of the big picture when making a ruling and how it affects class ability, spells, skills, etc.
It's not that abstract when the rule says you can't see; players are arguing you can see because of a comma; and then you have people in this thread saying in real life legal definitions of blindness include some sight so this should have some applicability to the game.
On those levels it doesn't matter how precise and complete the rules are written - those types of people will argue it anyway.