In my experience muscle memory is just as easy to pick up with typing the name of an app than clicking - apps I use all the time I can open by typing their name without thinking about what the name is, apps I don't use all the time I find myself opening the metro start screen and wondering which will happen first, remembering the name to type or spotting it in my tiles.
You're right. Though at least on Windows 7, typing to search apps in the start menu was a miserable experience that takes dozens of seconds to find the application you're looking for. I hope they have improved it in 10.
