You "fail to see the problem" with a financial institution encouraging insecure handling of CC and acct details? I hope that you don't work for a bank, but somehow I suspect you do.

EDIT: I'll take your deletion as confirmation that you do work for a bank.

Yes, banks and "security procedures" are about the bare minimum security and CYA

And by "bare minimum security" usually means ensuring there's a padlock on a 3 foot tall gate

I don't think that it's something you know, (the last 4 of your credit card or social security are used for that).

My guess is that they have different email campaigns tied to your bank account, credit card or investment account, etc. This is probably the only way to make sure you don't get any emails from that account.

But they want my Credit Card + Bank Account No + Cellphone no. This is a link that was in the email. My first instinct was that this was a phishing email. Then when the link appeared genuine, I guessed its their way to discourage me from unsubscribing.

"I guessed its their way to discourage me from unsubscribing."

This is likely to be a new internet monetization scheme... Go ahead, mark this as spam, you'll never get another water utility bill again. To save money on your water bill, we send you these marketing messages every day.

You can't be serious, like every major site out there will send you an email link with a "password" unique to that user/email that will one-click opt-out. I believe this is due to US regulation, but it's clearly technically implementable and safe.