Comment by tsungxu

It's actually not a terrible inefficiency.

With this config, the cruise motors and prop are optimally sized for cruise - which gives non trivial gains to both eta for propulsive motor efficiency and prop efficiency.

Vs a tiltrotor/wing/body in which the cruise motor has to do double duty as lifting motors. Given it takes anywhere from ~4-7x more power to hover (depending on disc loading) than to cruise, you can see how the motors are not in an optimal throttle/rpm band in this case. Archer's CTO Munoz has actually said this publicly.