"Absolute power corrupts absolutely"  How soon until the Congress realizes the disaster they are courting if they don't force the President to create a truly blind trust or to divest himself of his interests. This strikes to the perception of  the legitimacy of the government by the governed.  The Emoluments Clause, of the Constitution was put there exactly to stop foreign influence including that which could be obtained by allowing  profit to be routed to a sitting President regardless of his "promise" to donate this profit.  How else could those "donations" be proven other than by his releasing his tax returns and risking penalty for submitting a false tax return?. 

Emoluments Clause: "No Title of Nobility shall be granted by the United States: And no Person holding any Office of Profit or Trust under them, shall, without the Consent of the Congress, accept of any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince, or foreign State.