I grew up in China and have been in China a few times in the past 10 years - the amount of Robocalls and phone scams was overwhelming (in fact, it was so bad that dual SIM mobile phones became popular because you can have a disposable SIM card for non-essential website registrations and one for family members that you keep private use). I had my identity stolen after somehow I went into China Mobile pop-up service storefront in PEK airport to get a local SIM card. People on the line on my back was so close to the counter and peeking application forms with all sorts of private data, which made me very uncomfortable. There are also organized gangs that are operating in selling people's private identity data like mobile phone numbers. Later it made sense how my identify was stolen in retrospect.
Also, mobile phone number is essentially Chinese citizen's digital identity in a way in that 99% of the website/online services use mobile phone number instead of emails for authentications and 2FA. It's nearly impossible to sign up for any Chinese website without giving your mobile phone number to complete the sign up.
Given China's mobile-centric Internet boom, the amount of phone scams and frauds and identity thefts going on and all businesses (including financial institutions) are relying heavily on, it's a reasonably measure to counter fraud with real identity tying in with mobile phone number issuance.
So no I don't think it's a political motivated move, even though the side effect is making the abuse much more convenient.