Uh, because the footage is BetaSP and they want the best quality for TV.
How else is he going to get it into the system? Route the Beta thru a camera or converter box and compress 5:1? Let's not backstep out TV production. DVCAM quality is "decent" and "acceptable." Even BetaSP is at the bottom of the acceptable broadcast formats. Why worsen it by going in at DVCAM quality?
Let's raise our standards when we can...