Trace frowned and wiggled her hoof in a noncommittal sort of way. “Well… yes and no. The fundamental motive’s the same, but one can share the elixir and it has no need of the deaths of other ponies in the creation of a phylactery. I once heard of an alchemist who wanted to share it with her family. If you become a lich, you’re knowingly screwing over a bunch of other ponies in the process. You’re scared to die, so scared that you’ll do anything to stop it. You’d rather save your life and lose your soul than vice versa when any sane pony would stick with vice versa. Plus, the philosopher’s stone also gives you gold, which in turn gives you threesomes.”