twocats I can't argue with your experience but wondering if we're hearing different things due to the devices? I hear a huge difference in the articulation.
I listened with a good hifi system: I don't think the device is in question. I know that visual clues will affect the way we hear. I also know that tactile clues will affect this even more: the fact that you felt the difference while playing those examples would undoubtedly affect the way you heard them as you played, and could continue to affect the way you hear the examples when you watch the video.
I know you didn't intend this as a test, but I would contend this: if you used that particular example as a test, asking people to listen to it with no visual clues, they wouldn't be able to discern when you were lifting your hands between notes and when you weren't.
twocats When I see a legato line it indicates that I should shape and phrase it. If it's staccato the composer is trying to tell me that they want it crisp and mechanical! The result should sound different.
Certainly, in order to give the listener the sensation of legato, shaping and phrasing are important. Here's a question, though: if the pedal is down, does playing the passage with a joined finger technique help to create the required musical effect? I say: not necessarily. In some cases it may be detrimental (for instance if joining the notes with the fingers requires stretching or twisting the hand).
For me, a true legato is this: a musical phrase where each note grows or dies seamlessly into the next one. This is only actually possible if the phrase is sung, or played on a melodic instrument such as a violin or oboe. But the best pianists can create a convincing illusion for the listener.