[mobiplayer]

That's too simplistic, and as expected wrong.

Some of those regions are known for being proud of their language and culture, so in case of similar specs and cost many people will chose a vendor that covers their native (or L2 but local) language instead of one that doesn't. Something to take into account is that e.g. Catalan (or Valencian or Balearic, you name it) represents between ~9M and ~11M native and L2 speakers (depending on sources). What else... Oh yes, the regions where Catalan is official in Spain are among the wealthiest when considering the average income for its residents. That sounds like a good pond to fish for early adopters. Basques with even less population (and less L1 and L2 speakers, even in % than Catalans) are also among the wealthiest. The use case doesn't seem that narrow anymore, doesn't it?

Every single big company in Spain is able to communicate in any official language. Dude, it means business!

Finally, and I'm leaving a lot of stuff behind, people are usually not very thick skinned and calling the support of these languages "very limited use case" could be considered, well... inconsiderate at least.