If a Blu-ray is $20 on release day and the same movie is $25 on UHD 4K do you imagine that if they left the Blu-ray out of the UHD package that they would cut the price down to the same as a Blu-ray?
One is a premium product and one is a standard product. Basically they're just throwng in the Blu-ray for free to sweeten the deal. Some UHD releases do not contain a Blu-ray but - surprise! - they're not any cheaper than the ones that do contain the Blu-ray.
One is a premium product and one is a standard product. Basically they're just throwng in the Blu-ray for free to sweeten the deal. Some UHD releases do not contain a Blu-ray but - surprise! - they're not any cheaper than the ones that do contain the Blu-ray.