It's definitely nice, but honestly, isn't much of a factor for me as what app is going to come close to using that power? What app comes close to using the a10? With apps having to support 5 year old phones, nothing will be taking advantage of this awesome new processor. Since iOS is so simple, and can run well on weaker hardware, much more powerful hardware doesn't really change the user experience that much.
Personally, I don't notice any speed increase with my iphone 7 in apps and moving around the OS compared to my wifes 6s which had a much larger relative single core speed increase, which is more important than the multi core score as again, iOS is relatively simple and doesn't have real multitasking.