[ProfessorLayton]

It's likely just economies of scale, similar to how almost all cars, even the cheapest ones, have electric windows. It's cheaper to include them in all model tiers than to keep a separate SKU for roll-ups that'll barely sell anyway, because they exist so they can say "Starting at [lower $]" than what dealers actually keep in stock.

This kind of stuff happens in tech all the time, like lower tier CPUs that are actually manufactured as higher tier ones, but with CPU/GPU cores disabled even if they weren't defective.