The ability on Scheming Fence has a lot to offer. In commander the easiest way to activate it is to simply shut down a mana artifact or a mana creature, and ramp yourself instead.
But that's only the beginning! Think of all the hexproof and shroud creatures that suddenly lose those abilities, or Phyrexian Revoker that suddenly can't block your cards anymore.
It can also go infinite with Kiki-Jiki, Mirror Breaker, and so on and so forth. The possibilities are endless!