For me it’s not so much about the readability in sunlight, but about being able to glance at your watch without moving your wrist and about the watch not emitting light in dark environments. I find that distracting and I like the stealthiness of MIPS. That being said, if the minimum brightness is low enough and battery life with always-on high enough I think I could live with it, but with wrist gestures completely disabled except during activity.