because with offline I:
a) don't have to worry about finding a time when both the cpu and I can play
b) don't have to worry about online lag
c) don't have to worry about the cpu "cheesing"
d) don't have to find 31 people that are going to stay interested in my franchise and see it through to the end
e) don't have to worry about the cpu pulling the plug simply because he's losing
Those are my reasons. I have nothing against online play and understand that there are others who enjoy it, but online play is not for me.