there are a lot of times it is a dead card. it can aslo be card disadvantage.
There you have it. That's we we don't usually run it (at least part of the reason, anyway). Why would you wanna imprint a wished Pulse when you can just wish for a Rack and Ruin? It costs less mana, is less conditional and does the job more efficiently (2 artifacts for a total of 6 mana, at instat speed spread over 2 cards instead of 1 artifact for a total of 7 mana at basically sorcery speed spread over 3 cards or possibly 2 artifacts / 9 mana spreasd over two turns)?
You usually wish for an answer to a given situation. Playing that answer once does the trick 99% of the time.
Scpeter can be run in Keeper but then you have to more or less build your deck around it (Thug's Scepter Control Keeper build, for example).