Originally Posted by
Tofino87
It might be because [...] they don’t want to just give away free airmiles?
Precisely. If you read around on this topic, here and elsewhere, you will find reports of people successfully transferring bonus or purchased points out to airlines. But it's clearly not something Meliá intends or wants people to do.
I would certainly not recommend buying Meliá points, especially the quantity you're considering, unless I actually wanted them for Meliá hotel stays.