Yeah, logic would seem to dictate that magnetic pedals will purely be there only to minimise the chance of your foot bouncing off the pedals if going over bumpy terrain akin to a MTB trail, and to aid putting your foot back on the pedal in the same place every time. They simply can't help in applying power through your legs upstroke, otherwise you'd never be able to detect your feet!
Take the plunge and go clipless, it's honestly not as scary as it sounds. I know as I'm writing it I'm setting myself up for a fall here (pun intended) but I've never had a clipless moment, I've simply found clipless pedals brilliant in all ways. The thing you should note is that for all the posts about falling, I've yet to see one single post where someone says 'tried clipless, didn't like them, going back to flats'.
For the record I use both SPD-SL on the road bike and SPD on the MTB.