Actually, you can't really trust that behavior if you ever install new software, or even change the way you use the computer by say starting to use some other p

Actually, you can't really trust that behavior if you ever install new software, or even change the way you use the computer by say starting to use some other program that starts with a "t" very often. The Dash optimizes for programs that you run frequently and some other program might win out if you run it more often than "terminal". The Dash is based on giving feedback to the user; that's why it needs to be fast.