I agree with a lot of your points but I think you undersell the problem with the "1%" cases.

The problem isn't fixing it. The problem is detecting it's a problem in the first place.

Stack this with dozens of over "1%" cases and you're in for a world of hurt.

So yes it doesn't matter. But it also does.

This reminds me a bit of security at our company. "Technically I don't need to escape that because it's just an integer." My response always is: technically you don't have to, but technically every dev who reads it needs to check that its an integer. Make the code obviously correct.