Legal address doesn't matter for mail, and all of this stuff is about mail/shipping. This includes billing addresses.
I would have assumed that you knew that. I know people whose ZIP code belongs to a neighboring town (because mail works that way) and it basically becomes their de-facto address.
Some areas have duplicate, or very similar street names (ie, 'ave' vs. 'street') I don't think its that much of an ask that a website lets you enter your address correctly
Probably not safe to assume my level of knowledge about any subject matter
The legal address can absolutely matter for shipping when there are legal requirements in regards to the thing you’re shipping.