Why does LinkedIn switch to an unspecific number after 500+ connections?

LinkedIn displays the number of connections a user has very prominently on their profile, in the top card on the page.

However, once a user has over 500 connections, it switches from a specific number to an unspecific number, and shows '500+' instead.

What are the benefits to a) the user, and b) to LinkedIn of not being specifying the number of connections over 500?