One of my main reasons for wanting to have a ukulele, was the ability to play in any key. My sister has just decided to take up the banjo. She loves bluegrass, and everything she has learned so far is in the key of G. My dulcimer is in the key of D and G is hard to get to.
The other reason is that I can't find a comfortable place to play the dulcimer. It won't stay on my lap and I hate being strapped in to whatever I'm doing. I jump up and down too much. Besides, I don't have much of a lap left. I don't have a comfortable chair for the dulcimer either. My only two chairs are a low slung lawn chair and a straight chair that is falling apart. The dulcimer is too long to fit on the first and the second is stationed in front of the loom and not easy to access.
The little ukulele fits right in my lap and takes up hardly any room. I can relax in front of a movie on the computer in that low slung chair and practice chords or strumming.
My fingers are pretty large and I'd love to have a tenor uke. But for now, I'm happy to have this little antique.
Here's a video of some members of the Ukulele Orchestra of Great Britain playing even smaller ukes.