Era of 2.2V Supply Coming?

It appears that Samsung starts to use 2.2V supply in its new pixel designs:

• Samsung newly announced 0.64um pixel in 200MP sensor uses 2.2V supply, while the "old" 0.64um pixel in 50MP sensor announced in June 2021 still relies on 2.8V supply:

• Samsung new 1um pixel in 50MP sensor with "all-directional" PDAF uses 2.2V supply too.
• Apparently Samsung modifies its "older" pixels to adopt low voltage supply, similar to the 0.7um pixel presented at EI 2021:

"By reducing a pixel power supply voltage (Vpix), power consumption for pixel was reduced, but full-well capacity (FWC) was also decreased. However, by lowering the conversion gain (CG) and applying a negative voltage to the ground (NGND) of the pixel, FWC of 6000 e- was achieved without any degradation of both charge transfer lags and backflow noise. In addition, the signal linearity in the reduced analog-to-digital (ADC) range was improved by optimizing the source follower (SF). For dark performances, white spots and dark current worsened by NGND were significantly improved by forcing more negative voltage to the transfer gate (TG) when it was turned off."

• Another version of 2.2V pixels with negative-bootstrapped PD substrate was presented at 2020 ISCAS: