Questions about BE

Assumptions. I play 3 games a day. I can get 150 IP+50 IP through the first victory in the past. Assuming I can get 50IP per match. (50X2=100 IP) 150+50+100=300 IP (day) 300 IP (1 day) X 10 day = 3000 IP (10 day)

And now, I can only get 50 IP through the first victory. I can't get any IP in other games. Only experience can be obtained. BE collection speed is relatively slow.

Another problem is When you can play all game modes at 30 levels, Why do I need to give up BE / IP income, to enhance the experience level ?