I see your point, but it could just be that the 'best' system is just what you're used to (akin to the Celsius vs Farenheit argument). There's a load of systems that are slightly different between countries, and make perfect sense to those using the system but make absolutely no sense to anyone outside that system.

I guess the best thing is that this has created some awareness of the minor differences which may save some confusion later down the line should anyone visit a country using a different system.

To sort of answer your comment though, I don't see the ground floor as the "first floor" you'd be on because it's just the ground. It's hard to explain, but that's just what I'm personally used to, and saying the ground floor is the first floor doesn't make sense to me. Because I'm used to the "ground" system I'd know that if someone said something's "on the first floor", and I'm in my country, I'd go to the first floor above the ground floor.

If I went to the US for example and someone said something's on the first floor I'd look at what I'd call the ground floor, because I now understand that it's different.