Microsoft has however pushed out an update to the Cortana app on Apple App Store, and they have been very clear about how much improvement we can expect to see, that being 20% to be exact.
Microsoft claims version 2.6.7 of their digital assistant will offer 20% faster launch speeds, and the improvement is reportedly very noticeable.
Microsoft is also touting further unspecified performance fixes for higher levels of productivity.
Cortana on your iPhone is a good adjunct to a Windows 10 PC, allowing you to set a reminder on your phone and have it go off on your PC, or set a location reminder on your PC and being notified when you enter the designated area on your phone.
This is of course on top of a number of other useful features.
You can update the app here from Apple App Store.