[kryptiskt]

The different casing conventions is a signal indicating what kind of value the identifier represents (macro, local variable, type etc), it's actually doing work and isn't useless embellishment. If case didn't exist to signal those distinctions, other means would have been used (like the m_-prefix for members in some C++ styles). So the existence of upper case and lower case certainly isn't to blame, programmers would be free to use just one if it sufficed for them (and there was a time when a lot of programs consisted of upper case only).