Well, as I have many Duplos at home (I got a 2 yo kid which is a Lego enthusiast), when I want to "physically" build something, I use those, instead of LDD.
Of course, the size and colors of the bricks tend to limit the results, but Duplo can also be useful to build something nice.
These are starships I made for my little kid, and he enjoyed playing with them at least as much as I enjoyed building them (and it was much!).
Frigate
Cruiser
Carrier/Battleship
Does anyone else build something with Duplos for their toddlers?