Does it even matter when you sign your name on the digital device when making a purchase with a credit card?

I’m not expert but if you were to dispute the charge, it would be hard for the retailer to prove that it was actually you who made the purchase. It kind of their slip up.

Also if Visa found out for example, they could be in some pretty hot water with their payment gateway provider, and might have to pay fines, or lose the ability to accept credit cards.

The image is held, and if there is a dispute they use it to verify that you used the card yourself.

I have let my Granddaughter sign for me numerous times and she is only 5 years old. I do not think anyone ever looks at the signature.

Probably not. I suspect it could come up in a court case, but I’ve never heard of one.

It matters exactly as much as signing a physical paper receipt. Which is to say, not at all.