I find this popup really annoying. For me enabling the use of mobile unlock is way slower than me entering my password. I can enter me vault password in at most 3 seconds, probably way less. If I were to use it have to get my phone, unlock password and find and respond to the message, I often have several other prompts items stacked up on mobile device, none of which I want to deal when working on my PC.
There are two things missing with this popup. One a way to say no (I common problem with lots of Norton prompts for suggested features). Currently the best you can do is close it. And the other is the option to respond never ask again.