How often do you use powerful/extraneous objects?

I haven't played with these much (once in a moon option could fit too). I have cloned a sim. I've tested a relic. A family of mine has the crystal crown but I've never used it. What makes it so powerful? I have not used the weather machine, but I've recently placed it on two community lots. Yeah I think I want to incorporate some of these more into my gameplay. Would only use them with specific sims though.