Secret service alone has dumped over a million dollars into his hotels due to him staying there, now imagine all of his staffers and foreign groups that stay there to meet with him. And remember when he diverted a helicopter to his Scottish five-star hotels and then charged the government for them to stay there? There are also the shenanigans about his campaign finance expenditures including overpaying his hotel for the inauguration festivities.
The first argument is not compelling. He has more than spent what would have been his presidential salary by his record-setting golf trips. If he golfed the same amount as his predecessor and taken his presidential salary, there would have been even more money available for those causes.