@Aram-Pink-Zebra#58980 Bunq has said (I think even Ali) that this is on purpose to prevent fraud. He did't exaclty say how this should work though.
I guess it's for that when someone creates a bunq.me link like bunq.me/PimFortuin people can check where the money goes.
I think it's a privacy leak, and don't really see how showing the IBAN helps. If people know the IBAN (or look it up) to see it's not actually the account of PimFortuin they could just enter the IBAN in their own banking app, right?
However, in the Terms & Conditions of bunq.me it clearly states that you give them permission to share your name and IBAN. Note that someone has to know your bunq.me-link for this to work anyway
If you don't want anyone to know your IBAN you can remove your bunq.me page and then it won't work anymore.