Increase of vitality, imune system, consciousness which includes emotional order, environment awareness and then an increased sensibility to the beauty of nature. Deep feeling of being at the right place. Globally a very enjoyable inner state. And more.
Most people enjoy that from a healthy, balanced lifestyle that includes some meditation. But spending most of your life focused on meditation doesn't seem beneficial.
Dry sheets, according to the article.
I mean, it's certainly useful to be able to raise your body temperature. I've done a bit of biofeedback and can raise my hand temperature by about 15°F in a few minutes, although not if it's really cold out. I assume if I practiced more, it could actually be a survival skill.
If you asked the mystics, they would probably say none whatsoever. Why spend your whole life learning how to walk on water if you can pay the boatsmen for a ride?
If it is all that you want.
Exactly. Obviously there are advantages to meditation, but THAT much... diminishing returns.