The worst with these formatting is that Excel will behave differently in different regions. Another headache in large international corporations/collaborations.
But that's an advantage too. As a non English-native user, I like when companies care about my language and culture and they do not stick dates to the MM-DD-YYYY format that is used by Americans only. Yes, of course, we should all go for YYYY-MM-DD... fine by me, but now you go telling my mom :¬)
