Thanks for the question!

I have thought about this question at length. There is no way to verifiably prove your human movement to a computer system. Therefore, yes, you need to use POW to update your location in d-space to reflect your actual location.

It takes about 1 terahash/second to move 1 km/hour in d-space. You would need to delegate POW to an ASIC or at least a couple GPUs at home; they could hash and update your avatar's position as you moved around with your mobile phone.

Until phones get a lot more powerful, delegated POW would be the only practical way to mirror your walking position with an avatar in d-space.