Your points best apply to situations where the end user is the same as the person named. While this may seem to be the case for most web applications, let's not

Your points best apply to situations where the end user is the same as the person named. While this may seem to be the case for most web applications, let's note the interesting results on, say, Facebook when trying to even search for already-made friends whose '7-bit use names' might not be the ones you expect. (In fact, I recall odd results from Facebook when searching without accents, which are generally require special attention to enter on a US keyboard.) Further, if you live in the US doesn't mean you've lived there long. Are you ready to cope when the user hasn't settled on, or perhaps even understands, the need for said use name? Heck, US population is 4.4% -- who's focused on super-minorities, now?