I suppose I should say that McBride actually has two kinds of cards for manipulation. He as the older ones and the newer ones. I own both but have only played with the newer ones. (I want to keep the older ones sealed because I'm a dork like that ) I suppose they could be prepared like regular bees and used for manipulation. The card stock isn't terrible, but for something that is sold as a manipulation aide they don't really offer anything over your standard Bees. In any case, I encourage you to try them out. Perhaps there is something that you will find appealing about them. I'm just putting my own experience out there.

My theory is that Jeff probably has a lot of his cards lying around, so he may as well use them as opposed to buying cases of Bees or Steamboats.

As for cards with four pips..this is a feature usually touted by manipulation card brands so that fans look the same in both hands regardless of how they are fanned. It's not a feature that matters a bit to me, but to some it might. Also I should mention that in Europe nearly all playing cards you buy have pips on all four corners, in addition to being what we consider "bridge size." I haven't tried manipulation with European cards but I'll probably give it a go while I'm here.