This is a great question and we see it a lot. Really, it highlights just how opaque FX fees are in the industry, particularly with large institutions.
It's important to notice that we're the only product that combines a fixed fee and zero FX markup. Banks are charging you a fixed fee, but marking up the FX rate by 1-3% typically. So you're actually paying 8 EUR explicitly + 1-3% hidden fee which, in total, is a (very high!) variable fee.
I wrote about just international money transfers within the same currency, not about currency exchange. These are different and independent services. It is true that the bank has high spread, so i do not use it for money exchanges, just for money transfers.
But as others wrote, saing 'zero FX markup' is opaque and nonsensical. Proper way to is just to annonuce your spread. Even companies that have some FX markup can offer smaller spread than 'zero FX markup' if they have balanced flows between currencies and can pair most of their transactions internally.
It's important to notice that we're the only product that combines a fixed fee and zero FX markup. Banks are charging you a fixed fee, but marking up the FX rate by 1-3% typically. So you're actually paying 8 EUR explicitly + 1-3% hidden fee which, in total, is a (very high!) variable fee.