You're missing the point of connecting an external GPU... If people wanted portable power for their laptops without worrying about size and battery life, they'd just buy a high end gaming laptop. The large market for this type of device is people that want to have portability, small form factor and battery life without sacrificing power when they're at home or in a hotel room or any sort of "home base." As much as portable technology advances, it will always be behind the power of desktop devices (or until battery power is equivalent to in-home power) and this is the perfect solution for the choice between portability and performance.
Also, for the record, the price of this enclosure is absolutely ludicrous, no matter what your profession is.