Most people will write down something for the sake of writing it. However, I don't necessarily think what you write matters all that much. Most schools believe you can learn the manual dexterity part while you're in school. In most of my interviews, my interviewers didn't even ask about my manual dexterity. The ones that did, I just told them whatever I wrote on my application and it was sufficient.
I said that used to play a lot of computer games, mainly first person shooters, and that it built my fast twitch motor skills/hand eye coordination. Lol a load of bs on one side, yet oddly true on another. It wasn't like I played video games with the intention of being a dentist, but inevitably you have done something with your hands besides writing (playing an instrument, crafts, etc). Just put something down, its not gonna be the deciding factor of whether you get in or not.