In a cruel joke, the souls trapped as Remnants retained their wealth, or lack of it, from their previous life, making Hell either very comfortable or very punishing. Some of the more generous Remnants decide to fund the Votive Houses scattered throughout the Ring, though I have long suspected that their motives are less than selfless.
Wickstone is effective on units who have the Burnout affix (assuming that it would be advantageous for the unit to live longer, which isn't always true). The bonus +5 Attack and +5 Health are also decent for a unit who already has good default stats.
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.