The Challenge Cup bit was just wrong. Double Teaming is at best a prayer for the Hax Gods to take you out of a losing situation, just like Swagger. Except with Swagger, you have pretty good odds of at least doing some damage, while Double Team will all too often do exactly nothing. The key to Challenge Cup is managing normal resists and normal STABs. Return is dirt common in CC, and a 150 BP move hits hard from almost any user. Toxic is a very viable plan B, so maintaining any steel types is an even greater premium.