I have this on my BMW 530e PHEV and it's really a good thing. Once you get used to it, you take your foot off the brake and move it over to the "gas" pedal (is this going to be a ubiquitous term like kleenex) ready for a quick start when the light changes or traffic clears. Until you drive an EV, you don't appreciate how the instant jump off the line puts you way ahead of ALL other traffic completely without "burning rubber". This brake hold on stop eliminates the half-second or so it takes to move your right foot from the brake to the gas and you are even farther out in front!
I certainly hope the ID.4 has this.