Absolutely! There are benefits to register with BookMyShow which would cost you nothing.
✓ Bookmyshow allows you to save your Debit/Credit card, Net Banking, Gift Voucher, UPI or Redeem Points details under the "Quick Pay" option. It makes your life a bit easier in terms of quick payment as you wouldn't have to enter the card details manually anymore.
✓ You could keep a track of all your bookings/purchases under the "Your Orders" section.
✓ Subscribe to the newsletters and stay updated about all your favorite Movies, Events, Sports, etc. You too get push notifications on the App.
✓ Apply for BookMyShow Play Credit Card
✓ Restaurant Discounts
There are exclusive offers on multiple banks that are available on your selected debit/credit cards, on multiple Mobile Wallets as well as, you may have a look at it here