My experience with the CRED app -
I recently installed the app. On the first screen, it automatically fetched my mobile number. I pressed continue.
In the next step, it asked for permissions. I attempted to deny everything, but it stated that SMS and phone permissions were mandatory.
I proceeded to give only those two permissions. Moving on to the third step, I received an OTP.
In the fourth step, the app asked me to add all my cards. It displayed some of my existing cards and required me to enter the full card number.
It showed that it would do a penny drop for verification purposes.
However, I decided not to add any card. I simply exited the app, uninstalled it, and left.
I received WhatsApp messages from CRED regarding all my existing cards.
My bill generation date for all cards is 12th and CRED notified me of all the bills via WhatsApp.
Somehow, CRED managed to fetch all my card numbers (possibly from SMS), and just like how Paytm and Amazon remind us to pay bills, CRED is also reminding me through WhatsApp.
I haven't added or synced any cards yet. So, for now, I believe it is safe.