butterworth configuration of multi-stage amplifier
Butterworth configuration is often used in three stage amplifier design because it is good compromise with transient behavior and power consumption.
Say if you design an two-stage amplifier configured in Bessel, which damps more than butterworth, so the non-dominant pole needs to be at higher frequency than its butterworth counterpart -- more bias current.
Another thing to look at it is ,  people trying to publish a paper talking about a new amp architecture, often wish to compare to previous work in some standard, that their circuits use less resources to perform better. Butterworth configuration is a good standard. The corresponding open loop transfer function of a butterworth configured closed loop amp has the property of independent phase margin regardless what order it is, 60. So some people think cross comparison of power efficiency between 3-stage/2-stage/4-stage is easier when we always have the phase margin fixed. But indeed I think this is sort of cheating, as gain margin does vary with order.
60 degree phase margin is usually enough to combat component variation.
Maximally flat property is also desired to avoid frequency domain peaking. Good for both switch-cap or audio applications.
Last, the corresponding third order open-loop poles of a butterworth configured unity-gain closed-loop amp can be viewed as a butterworth configured second-order closed loop amp adding a dominant pole, thus it is easy for people to design a nesting structure. And butterworth pole placement lies on a semicircle, which is also easy to calculate without too much messing with some polynomial coefficients, people are lazy in general.