I think "cameo" is the correct term. He didn't wait in line all day with 1000 others to be an extra; he was asked to be in the movie because of how easily recognizable he is, and he plays himself.
as far as i understand it he requires a cameo in any film/show that uses his properties (in this case the trump hotel). he wasn't asked. it was required. supposedly most of the scenes filmed by other productions just end up on the cutting room floor but that one was left in.
They didn’t ask him.
He added it as a requirement to film in the hotel since he owned it at the time.
As I understand it, he wasn’t asked to be in the movie but rather he made it a condition of filming in his hotel that he be given a cameo.