Over the years I’ve noticed “It’s good to see you!” is a line often used by famous people and politicians in an effort to avoid hurting the feelings of people they’ve met before (they simply meet too many people to remember them all). The phrase can be said to a new acquaintance without seeming overly weird, and it makes previous acquaintances feel as though they’re remembered from a past encounter.
It’s safer than using the more standard phrase, “It’s good to meet you,” which could be taken offensively by someone they’ve previously met.