The article 'the' isn't needed here
scump = dear and dear has two meanings as does scump. Scumpul meu and o călătorie scumpă.
I think that it is as good a translation and should be accepted
If you wanted to say that, you would add whom the destinations are dear to.
Attractive destinations are dear to me.
Destinațiile atractive îmi sunt scumpe.
Though this is pushing it a bit.
True, but as a native speaker, I would never use "scumpe", with the meaning of "dear", to describe a destination...