Because Cortana is the manifestation of engineering capacity to crunch user data to make deeper decisions and better offerings to end users. That capacity is why Google, Apple and now MSFT are all chasing the ability to do voice, because that means they can do highly sophisticated data crunching on their massive computational capacity.
It aligns directly with each's desire to deliver products and services (yes, even Apple - music suggestions is one example) rather than just be a hardware/software retailer.
It aligns directly with each's desire to deliver products and services (yes, even Apple - music suggestions is one example) rather than just be a hardware/software retailer.