[dangrossman]

Buying an iPad stylus makes it a little less awkward than asking the customer to sign with their finger.

[hkmurakami]

Also, some customers probably can't stand touching the surface of an iPad that's been touched by a hundred people before them.

[bhups]

Doesn't that apply to ordinary pens too, though?

[tehwebguy]

My assumption is that it's not as big of a deterrent because greasy smudge marks are so much easier to spot on a screen vs a pen.