There are fields in which it is helpful to bring in someone who knows how to abuse or manipulate a system in order to improve that system. Black hat hackers are often brought in by online security agencies to explain their tactics so that countermeasures can be prepared. Rely on criminals to explain how they do what they do is helpful if it is criminal behavior that has you mystified. Does the way some with the most resources avoid taxes a mystery?
Surrogates for Mr Trump are now describing Mr Trump as a genius because he has been able to take advantage of federal tax laws to increase his own wealth. Does Mr. Trump have insight that other politicians do not? I doubt that this is the case. The issue of loopholes afforded the very rich are well known and constantly noted by politicians. The problem is not so much with understanding or with the individual who happens to be the president, but with the unwillingness of congress to address the problem. It is important to understand that it is congress that makes the laws. Executive powers are quite limited in the area of generating the funds to maintain the needs of the country. This is one of those division of powers things.
The congressional representatives who could change the tax laws are heavily lobbied and supported by the wealthy. Ask those who represent you about the tax law.
The logic that a successful businessperson can use these same skills to benefit the country depends on what skills apply. As a leader of the country you cannot rely on bankruptcy as a solution to thee organization you represent. You pretty much have to pay those folks for goods and services you ask them to provide.