Everything has to come down eventually, but all else being equal, exposed steel is better for ease of access and maintenance than steel buried in concrete.
No, it's way worse. The outermost concrete layer serves multiple purposes, including corrosion protection and fire resistance.
Exposed rebar can and will start corroding immediately if not covered or treated, and in turn it loses grip and resistance.
I've been told its for tax reasons, something about not needing to pay taxes on a building that is still "under construction"