Rakdos Charm is cheap and instant artifact removal therefore trumping things like Torch Fiend in that role yet in its other, perhaps more situational uses the Rakdos Charm is not nearly as dull as a 2/1 for 2 offering you far more power
They might even have a use to kill the creature after it turns face up
But countering isnt always the most efficient way to remove mutated creatures because of the nature of the mechanic
Making your opponent choose between paying an extra 2 mana or giving you copies of their instants and sorceries is far more effective than I gave it credit for
EddCrawley on Commander 2015 10 years ago I bought the UG Ezuri, Claw of Progress and immediately swithed out about 12 cards, and took it to A casual game day at my LGS, and it went 2-0, mostly due to Sage of Hours and recursion of Eternal Witness and Verdant Confluence, plus card draw of Fathom Mage, with added life gain of Horizon Chimera, then there was the synergy of Hangarback Walker with Vorel of the Hull Clade please see my current deck list
The only real downside to this Toph, from a mechanical perspective, is her color identity