These wealthy residents of Hell are considered among the few to reside in the upper echelon of Remnant Society. They pay the bills for the endeavors of the Wickless, partial to the benefits it allows them. And since the Rail has brought them much business, some of that coin has made its way to our train.
Heartstone is effective on units that typically occupy the front line of a floor. Front line units are the ones that take most of the damage, leaving the role of dealing damage to the units safely tucked behind them. It can be argued that Wickless Tycoon is not a good front line unit, be he can act as one if you have yet to encounter a better option.