I've had to add this exact functionality ("Look left and repeat these numbers") as part of KYC for a mobile app similar to Revolut.

This is in conjunction with ID scanning.

I think this functionality was necessary as part of complying with KYC laws. And AFAIK WeChat has very similar functionality to Revolut (among much more) so even if the app was non-Chinese (e.g. European), it would need a similar flow.