I’m very suspicious about enabling either of the settings in ‘Profile findable by’ - ‘QR code or payment link’ (monzo.me) and ‘Phone number’ (contacts)
Seems like it’s too easy to find/connect with Monzo users this way - especially by loading thousands of random numbers into your phone contacts and enabling it. Some of those numbers will be Monzo users and you’ll see them. Then once you find a Monzo user, send a small amount. If it goes through, the target is acquired for the next stage - phish for the account details or the well-reported panic ‘fraud is happening’ call…