The problem with the Powerwash being required to switch into developer mode on a Pixelbook is that you cannot switch to having root and then introspect the integrity of the system (to compare against a previous version, or to do static analysis, et c).
Powerwash to go back into secure mode, I totally understand. But it makes it nigh-impossible to do closed-case forensics on a device if you have to nuke it to get root.
@sneak The point is that, in any state, it is supposed to nuke user data on any attempt at forensics.