We will see. 120hrz on my S21 eats battery life worse than 5g. Even on low power mode. I am sure they use similar algorithms for the technology. I just turn it off. Not that much of a big deal. Apple disables low power mode on 120hrtz. Use my iphone 12 and S21 frequently throughout the day. Not much difference between the screens. Guarantee threads complaining about battery life. Mark my words.
Not at all, it could be correct for a display intented for gaming / drawing or others activities with quickly paced interaction with the display.
You will notice extra comfort almost only while scrolling or with compatible games, which is not at all 100% of your time with the screen. Improving PPI like with retina, you notice it 100% of your time with the display since it's permanently exploited to its full potential.
While games might need to get updated in order to support 120 Hz this is NOT the case for regular apps, right? So e.g. scrolling etc. will happen in 120 Hz in apps like Twitter from the get-go, right?