Not taking crit into account, Double attack 10 gives you 50% more damage when ctrl-clicking. So, if you're ctrl-clicking vs monsters with low def that you can hit fine, then of course sidewinder card is way way way better than a 20% dmg card.
Against monsters with high def, or ones that you can't hit, crit becomes more useful. But against high-def monsters you're usually better of using an icepick.
So generally it's a great idea, but it depends on what you're fighting, and what your crit rate is. Use a calc to look at your dps vs the monsters you want to fight.