That's what it comes down to. Look at Hillary -- violating laws left and right. Look at Obama -- no respect for the law. Now, look at Cruz -- he follows the law. There's the difference.
Plenty of people realize that we now have a two-tier society. The laws are (apparently) for the little folk. The "important" people can ignore the laws. Well, Cruz is letting people know that he stands with the little folk.
He'll follow the law. Even when he doesn't like it. He'll pay his taxes. He'll sign up for Obamacare. He is not above the law.
But, given the chance, he'll make changes, and get rid of the laws that trouble the little folk. But the time for that hasn't come yet. And until it does come, he does what's right. Unlike the Power Elite of the Democrats (and too many Republicans).
Theologically this would be known as the “humility of Christ.” The “sons do not owe taxes.” But they can choose to pay to satisfy the formality and to identify with those who really do owe taxes.