I'm sorry you're being downvoted - for the record I've upvoted since it's interesting, even if we disagree in some aspects.

Since I still have the machine in question here, and I'm now interested enough to try and get some rough measurements, I've just videoed it with my phone (30fps video) and done some frame counting, both from a cold boot with nothing cached, and also a repeated launch.

Firstly from a cold boot:

It's hard to tell exactly when the keypress registers, but I believe what I'm seeing is the key being pressed, two frames later the hourglass appears, two frames after that the calculator appears. (The TFT screen will likely be adding at least one frame lag, but let's ignore that for now.) So that's somewhere between 166 and 200ms for a cold launch.

If I close the app and repeat, there's now just one frame between keypress and hourglass, and just one more frame between hourglass and the app appearing, so now nearer 100ms.

Looking at the videos my finger is off the key the first time the app appears, but not the second time - though if I made a special effort to release the key as quickly as possible I now think I could probably just about beat it.