Sorry, no scientific data to share, but I do have some personal experience.
The way I have been taught is closer to the “shclap” description than it is to picturing a tranquil scene (and your dismissive tone is duly noted).
We are taught to sit or kneel, with spine straight and hands palm-upward at the juncture of the torso and thighs. The straight spine facilitates deep breathing, and the palms-up posture is a “signal” to the body. Just as students are told to always study in the same place to create a “studious” attitude, the meditation-only posture helps set the tone for the meditation.
Close eyes; breathe deeply from low in the abdomen - this fills the lungs from the bottom, more deeply oxygenating the body. Direct your eyes upward - aim for a spot between your eyebrows. This keeps you from falling asleep, and keeps your eyes from “leading” your body into a drooping posture.
Now the hard part. Clear your mind. Don’t think. When a thought comes, dismiss it without comment. Don’t think about the fact that you aren’t thinking.
(Don’t think about the fact that you’re not thinking about not . . . oh, never mind).
In time, you’re able to achieve a statement of awareness without content. It’s an interesting mental state to be in, and very difficult to maintain. (“Hey! I’m aware! Oh - damn!”) Done correctly, meditation is really, really hard.
Now the benefits (disclaimer - what follows is anecdotal; YMMV). With practice, you find (okay, I found) that you can apply the breathing-and-clearing techniques when you’re not sitting in a quiet place. You can do it in traffic, in meetings - wherever. In physical situations, it enhances alertness and awareness of surroundings, and helps keep your reactions calm(er) and, I think, more quickly responsive. In human interactions, it’s very helpful in tense situations when emotional reactions would be a Bad Thing.
Why does this work? Beats me (yeah, I know - not very helpful, am I?). I just know that if I go too many days without at least twenty minutes of disciplined sitting, the wheels tend to come off a lot more easily.