I'm not exactly comparing their purposes but the reasons people buy them. To do a proper comparison you would have to ask every single iOS device owner if they bought the thing for games, as the main reason for the purchase, to compare them with a device that is only good for gaming. You cannot assume to compare purchase numbers between two devices if people buy them for different reasons even if some features of the two products overlap.

It's the same comparison that people keep doing with PCs and consoles. Everybody buys a console for gaming (which is slowly changing, granted) while not everyone who buys a PC does so for gaming.

In fact, I think that apple base turned 100-250 million folks into casual gamers is more influential than yet another console.

I don't think I'm getting my point across very well. I'm not disputing that a large number of people use their iOS devices for gaming, which is good.

I'm just saying that you cannot necessarily compare two devices on a 1-to-1 basis using sales numbers if the two devices are not comparable 1-to-1 in their usage. The iOS devices are versatile in nature and are suitable for multiple tasks. It's not proper to compare every single sale of an iOS device against every single sale of Nintendo's products. You can make estimates and guesses but I don't feel a 1-to-1 comparison can be made nor be fair.

To make a comparison like this I'd rather know the numbers of game titles sold per device. That comparison works for me because the purpose of buying the game is to play it, nothing else.