Honestly, I'm fine with this. I think most applications will be generally stationary experiences, and there's no reason this can't be adjusted or Apple introduce an "active mode" in the future for cases where it's needed.
What I'm happy about is not having to physically define or draw a boundary every time the headset is used. My Quest often loses track of its boundary and needs to have it redrawn.
Apple wants this to be primarily for A/R - not V/R. V/R is inherently isolating to users and those around the users. A/R allows a person to be present in reality, yet it’s greatly enhanced. I think that’s what they are after.