I find this rather interesting: according to EU rules, all consumers are supposed to be treated the same. Maybe there are different rules for the financial sector?
I have the Belgian card: maybe you can try with them and deal with them in French, if that's easier for you.
I would not recommend the Swiss one, as it's 2CHF per mile (instead of 1EUR), and also you get 1 mile per 1€ but only when the charge is in EUR. I assume that if you use a Swiss card it's 1 mile per 2CHF, but only when the charge is in CHF.
It is definitely possible to get a bank account in Belgium as a non-resident, but I am not sure about credit. After all, as RTW1 says, they can accept you and then give you a 100€ limit..