More pricey.
Quite long - if the surf sucks dry, reckon there is a greater chance of breaking your paddle.
The length will add to shaft flex, reducing effectiveness.
The connections of the handles may see structural fatigue.
Single-blade switch and maintaining a course will develop your core quicker.
'...true advantages of superior power, ease-of-use and maneuverability'
Hmm... Are the handles sold by themselves - can I put them on my kayak wing-blade?