So now even more space is wasted, making interfaces harder to use, but yes, the less important metric "how much time does it take on first use to spot a button" will shoot through the roof of you make the button full screen width (10x faster!). Thought it will fail to capture the more important metric of time wasted scrolling since a simple message doesn't fully fit on screen
And of course there are no user customizations to rectify these usability errors...
PS A great example of this awesomeness in action: on https://m3.material.io/components/toolbars/guidelines they can't even fit 2 (two!) toolbar buttons fully because the huge left/right buttons and all the extra white space padding and margins prevent the button content from being seen.
But there is enough space to fit all 4 (or at least 3 depending on text size and icons) toolbar buttons, and even if one doesn’t fit fully you could show its partial text, so navigation would still be faster without having to press the scroll button first and then the toolbar button