Reason 1: Rand Enterprises
His company, Rand Enterprises will buy up some businesses or buildings around the area. Rand buys properties on a daily basis, so it is not hard to imagine them doing some work in Harlem. Maybe Danny catches wind of this and decides to give Luke a visit. Another option could be that Danny buys up the buildings in Harlem to keep the bad guys out, a plus for crime fighting, a negative for flashing your cash.