Maybe Yuyuko told her to promote her services so she can get her own money. Or maybe to overcome a budget adjustment.
did you really think that Hakugyokurou/yuyuko can obtains some money for youmu to even buy some basic food in any way? (might be yukari's doing but come on, being yukari's old friend ain't gonna get you free money)
this is not for a budget adjustment, this is the budget
or youkais get a lifetime "free money" card and youmu just want to have some more work to do, who knows