Not all features or Apps are available in every region, some being restricted by local laws or legislation. The country in which the device is marketed/sold will determine which features are accessible. FaceTime, by example, is not available to devices purchased in many Middle East countries.
Apple doesn’t exclude FaceTime from their products because they have a choice - they do so because local laws prohibit use of certain services (in this case FaceTime is prohibited by law in UAE).
In this example, Apple products sold in UAE don’t incorporate services that are prohibited. Technically, the product’s region-specific model number will inhibit loading of Apps that are not intended for use in the region in which it is sold. Removing the product from the country of purchase does not lift this hardware/software restriction.
Some other countries have similar restrictions - that prohibit the sale of products that do not conform to their laws. These restrictions don’t just relate to services and software, but may also apply to other characteristics (physical, electrical etc.)
