I got tired of buying magnetic nutdriver bits separately. I also wanted a set that would fit into a magnetic bit extension I have. This Milwaukee set is made to order. They are color-coded, which helps me quickly retrieve the right one from my drill pouch. I use these with a Milwaukee V28 drill, but you could use them with anything that will handle a nutdriver. So they would work in a magnetic handle, a magnetic bit extension, just the chuck of the drill, or even non-magnetic systems that use a ball bearing to lock the bit in. That is what that divot in the end of the bit is for.
The heads of these are tapered and yes that has come in handy several times. I've found myself trying to squeeze the nutdriver head into a tight spot and that taper made the difference.
My only complaint is that I've already managed to chip the magnet on the inside of one of them. I chock that up to normal wear and tear though. It's happened with other nut drivers.
These nut drivers are also impact-rated. So you can be sure that the shank won't be shattering in your face. Don't make me remind you to wear safety goggles.