Forgive me if I'm totally wrong here, as I haven't done any research on capacitors in a few years but I'm thinking I remember something.
The energy output of a capacitor is a reciprocal graph so you massive output in the first second, then a huge amount less in the 2nd (times purely example, I don't know the actual output times). Wouldn't, in an F1 car, a more consistent level output be preferred? A huge quick burst would spin your wheels up whereas a lower output for longer ups your acceleration without messing your wheels by spinning.
Might be totally wrong. It's been about 3 years since I looked into that stuff and even then only did it loosely with a focus on other techs anyway.
Used in combination with a flywheel? Or don't use them all at once, sequentially, or something?