Are you on the team? Was there a clamoring from the users for infinite scroll? Was there a study of how it would effect the typical user?
But the reason I stated it is that A: it was a heavily requested feature B: comments regarding infinite scroll have been weirdly positive (contrasting my point in another reply about most comments are from very strongly opinionated users) and C: usage statistics ie I can assure you when compared side by side people make more of the equivalent page turns. Personally I like both methods but infinite scroll was a clear winner for us.