„Good suitcases are expensive.” should be accepted, too, even though the Romanian equivallent has a definite article. This is because it is a general statement, which requires an article in Romanian, but it does not in English.
I just tried, "Good suitcases ..." and it works now.
I agree. You might want to report it.
I wondered about this. I know some languages use a definite article in places English doesn't, but I don't have enough feel for Romanian yet to know when and where it happens there.