Generally when a campaign uses their own offices or assets, they are applied as donations as 'services in kind' for the value of the service. In other words, if Joe Smith uses his home office, he categorizes that as a donation to the campaign 'in kind'.
This isn't being done this way, this is actual cash disbursements to these entities and people (ie, himself) including paying himself a salary.
In other words, he's funneling campaign cash - real economic value, not just "taxable income" - back to himself. Or at least back to companies with his name on them. Perhaps it has to be done in cash and not in kind because Trump doesn't really own those companies or else has restrictions from creditors that prevent him from making in kind use. That suggests he's a lot poorer than he keeps saying he is. I guess his "wealth" is just one more "truthful hyperbole" he likes to tell other people.
It's a good thing he's not made of wood like Pinocchio, otherwise his nose would be long enough to be out there at the heliopause with the voyager spacecraft.
