Wallet is one of the good feature in Paytm. we can pay without using our bank account. I did not find log in option other than OTP. Paytm Security Shield uses the device's scren lock pattern,PIN or password which is very unsecure as sometimes we do not use screen lock or use a simple pattern, pattern or Password Sometimes others lend our device for use or in case loss of our device, money can be misplaced or theft.