I was talking about real world situations in my early post, not about "the focus plane is just one and one only", which I agree to, but it isn't relevant for what we were discussing, and then, I'm pretty sure the other guy was actually meaning "if you misfocus, then the DoF won't save you", which is actually not true...so, NOPE
Just simply read what I wrote again. While DOF might "save" you (if you don't magnify all the way into the image), but it is still misfocused nevertheless, compared to how it should be. It also depends on field curvature, which with some lenses can be unforgiving in a studio even at f/16.
It does not matter if it the 28-70 f/2 or the 24-105 f/4 or if I step those down a couple of stops, I can still tell if the camera focused on the wrong eye even if they are almost at the same distance (maybe there a slightest amount of focus shift, but it is 99% misfocus).
And again, I'd like to reiterate that less DOF can actually be
helpful if the peaking in the EVF really highlights what's need to be in exact focus without magnifying. In that way, a Noctilux can be easier (or more straightforward) to precisely focus on a mirrorless camera than a Summilux while more DOF can actually be a hindrance to precisely manually focus (or the difficulty
does not automatically decrease by stepping down as long as we are talking about correct focus in the first place...)
The main takeaway from this is that while most people prefer the convenience of AF which definitely vastly increases the range of images one is actually able to take, manual focusing it not nearly as difficult as people make it out to be either (as long as people actually do it...) or at least with my lenses I certainly do not find stepping down to be much of a help compared to just staying wide-open.