It was a temptation to keep Tricki on as a permanent guest because b) Tricki did not create problems.
Why it was a temptation
In the story, we learn of a narrator who was excited about the luxurious things and foods he was getting as a result of Tricki's stay with him. Tricki was sick and recovering from a sickness. When Mrs. Pumphrey heard that he was still convalescing, she made arrangements for him to have food and fruits to quicken his recovery.
The narrator of the story was excited about this and that was why he wished that Tricki would stay longer so that he could continue receiving these things.