To each their own. Everyone just do what they are comfortable with, for whatever personal reasons. You don't have to give in to pressure if you don't want to.
Numbers and various parts of ID's are a funny thing these days.
I am one of a handful of people in a company of 300,000 employees that has access to ALL personnel data, past and present and the responsibility to safeguard it and send out bits of it as needed.
The level of approval and security measures I have to take to send an internal HR client a short list of employees that happens to have their full birthdate (month, day, year) is amazing.
Yet almost everyone on my Friends list on Facebook has their full birthdate listed right there on their profile.
It's all relative to someone's preference and level of paranoia.
