Accepted BB Offer- Now Invited to Visit Offices Before Internship- Normal?

I'll keep it brief:

I accepted an offer from a BB for a summer internship. I've been in minor contact (1-2 emails a piece) with my interviewers and all have invited me to the offices before the internship starts in June.

Is this normal? If so, is there really anything to gain from visiting the offices? It is highly unlikely I'll be working with 2 out of the 3 interviewers.

I live in NY, so the offices are only 15 mns away as well.