It doesn't involve the mouse at all.
press windows key.
start menu opens, search field is focused automatically.
start typing, windows start doing an incremental search, heavily biased towards your most used programs in the list ordering, press enter if your choice is first on the list, or navigate with directional keys on the program.
Your method only works if the program you want is on the PATH, and if you type the full name of the executable.
Your method only works if the program you want is on the PATH, and if you type the full name of the executable.