I think it's highly dependent on the significance of the memento. I have physical credentials I received for a major athletic event I competed in, and never in my life would I consider taking a picture of them and throwing them away.

It doesn't sound like you were all that attached to the coffee mugs to begin with, in which case digitizing them was a good move.

I'd imagine this is part of the reason why my parents still keep my terrible first grade art pieces framed on their desks.