The orbs inside the altars are probably because the wizards from the guild are putting them there. If I could recall, Acantha and Vief are saying it is to maintain the runic energy to not run out of runes. Perhaps that is why the playable altars have those instead of the non "gop" related altars? But that is just a prediction, I'm not sure about the other altars yet.
Life questioned Death, "Why do people love me and not you?" In Death's response, "...because you're a beautiful lie..., and I'm the ugly truth."