The new EMR machines are for stations that currently have no retailing facilities, so being able to buy a limited range of tickets is still better than being able to buy none at all.
Currently, passengers at these stations can board the train, confident that they won't have to queue for a ticket beforehand, and that the guard will be able to sell them the ticket they want - on CCST - meaning cross-London transfers are no problem at all.
Once these machines are installed, passengers will have to arrive at the station well before the train leaves - who knows how long the queue will be with these itinerary based TVMs - on pain of having to pay the undiscounted Anytime single, a Penalty Fare or prosecution. Oh, and if you want to cross London then you'll have to rebook at London, even if that costs a lot more - sorry!
Now, I wonder which scenario represents the better customer experience...