Had me in until I saw the one controller multiple airports... So you're needed in two places at once then what? Good luck getting all the ratings and maintaining currency/proficiency.
I think that they could be advantageous at location that currently don't have towers and are extremely remote thus hard to get staff to go there and/or stay there. Thinking of Oz and Uluru... Busy enough airport without a control service.
The concept is still young and I'm not sure that the 'redundancy' issues have been thought through properly and how the CRM/Human factors for tech crews plays out.