i think there is need of simple authentication. i aware that i can choose from existing methods but still moodle must adapt with changing situation. with my experience about 35% students finds difficulty while signing in to moodle first time. and i think this must be resolved because admin is not able to confim users so fast. so there is no need to login your email account.
there are two options
1) authentication with truecallers api.
2) moodle should allow login users with their mobile numbers and verify their mobile numbers with sending otp.
readers are welcome to comment and share their view
