We might think so, but in the final analysis the judgement is likely to be made on the seller's claims of what it is suitable for, not what buyers might want it to be suitable for.
Not a comment made to be argumentative but a flag that if seeking redress for something not offered, failure is likely to follow.
By comparison, there are brands that make "all season" use a selling point, this rather suggests its not a given for all caravans.
I am a bit concerned that in your case condensation has played a role and will be fronted by the seller's defence, as an aspect not wholly in their control.
As you seek, you do need the services of a competent expert to identify where all the issues causing the mould etc lay. If primarily it is physical leaks, then your chances are way better.
All said, I wish you luck.