Supercomputers are designed especially for performing various tasks as per requirement. And these supercomputers have that much capability and potential. But considering supercomputer for mining is a bit hard and completcated task for a supercomputer.
Even still anyone can use the supercomputer for mining, but it will be not profitable in coming future as day by day contributing power and difficulties are increasing.
And It's my own opinion that supercomputers are not made for mining, so it will cost more to maintain and gives lower ROI.
A super computer is referred to as something which is exceptional at certain tasks and therefore I would say that dedicated Bitcoin miners ASIIC are very close to being a super computer. They are able to mine quicker than traditional devices and therefore would fall under the category of a super computer. A super computer does not necessarily mean huge specifications and quick at everything.