The ideal answer would be wireless, which also opens up the options for controls, including multiple ones. But even if this product were that, I wouldn't get enough use to consider it worth that cost.
The thing is grandiosely overpriced, presumably to recover the development cost in a hurry. The correct way to price such an item is to forego profits in the initial stages, which might be years, by finding a venture capitalist and making him a partner. He'll tell you the same as I do; if he thinks he'll cash in quick (beyond the tax break on writing off the development cost), say thank you politely (you might want to return and rip him an expensive education) and find someone else with brains and experience.
Even a wireless-operated manual change for a Rohloff should not cost more at retail than say two hundred pounds (plus VAT). No expensive machining is required if you use the existing EXT box* and operate the change with its existing cables cut short, or even stiff rods in tension if you can get your stepper motors mounted near enough to the EXT box. Then you need two stepper motors to pull the cables, one for each cable, a Bluetooth sender and receiver for each cable set to different frequencies (built in to the hardware), an up-down switch to trigger the BT senders on the handlebars, two rechargeable batteries to power the whole thing, a couple of small boards to mount the components. All these components are available for peanuts because the Chinese Communist bureaucrat-driven manufactory in repeated cycles grotesquely overproduces everything and then in a panic sells it off cheap. The BT items, for instance, are under a tenner the four including postage and VAT -- and that's at retail; the wholesale price will be ridiculously low. The two stepper motors are under a tenner each for hugely over-capable devices. The switch is free from any scrap yard (get it out of a pre-Ford Volvo -- those were good enough for Rolls-Royce) or a couple of bucks from China for a high quality switch. There's no need for software: all you need is for a voltage to appear on the pin of a USB socket holding your BT transmitter or receiver, on pair for gear-up, one pair for gear-down, electronic engineering so simple fools will mistake it as crude. Nor are you doing anything to interfere with your Rohloff's warranty: you've just interposed a couple of stepper motors in the control cables. The most expensive part of this scheme is two watertight boxes to IP67 or -68 for a low-down folder mounting or a bulletproof handlebar fitting, to protect the battery and the stepper motors from wet.
Shimano sold an entire system to automate a Nexus gearbox, including an advanced adaptive suspension with magnesium fork legs controlled by the same computer that switched the gears and drove the sensors, for a sum that added about Euro 400 to 600 to the retail price of prestigious European bikes**. That means the Shimano delivered price of the gruppo to OEMs was in the order of Euro 200 to 240, and you were assured of a responsive brand name behind the product, with spare parts for several years.
Compare a boutique gear-switching system, which does only a very small part of what the Shimano system did, for almost a thousand pounds, roundabout 80 percent of a complete Rohloff gearbox and controls. It's nuts. The developer is essentially demanding that the first few adopters pay all the development cost, which in turn means that very few will be sold and the developer will go out of business, so that the first adopters are paying through the neck for a guarantee of their product being orphaned. You don't need an expensive business-school education to see that this is a perverse startup plan.
* I suspect you could do the same with the internal switching cables such as were fitted on early Thorn Rohloff bikes but I've never had a Rohloff without the EXT box, so I don't know what is involved. The point isn't where the cables go into the box but that they're both pull-cables.
** My Gazelle Toulouse, when it was the top model without the automation, sold for about 800-900 in The Netherlands. The Gazelle Saphir, the long-running model with the automation, sold for about 1300-1400 in the home market.