No, they must be each other's conjugate in order for the sum of the SOURCE and LOAD's reactances to be zero. In fact, they must be conjugate when seen through the transmission line connecting them, which will transform the LOAD impedance seen at the SOURCE and vice-versa, except in the specific circumstance that the LOAD/SOURCE impedance equals the transmission line's characteristic impedance.
With regards Maximum Power Transfer being unnecessary - it's perfectly true. Typically designers will look at load-pull data, with contours plotted on a Smith Chart of constant output power, constant efficiency, etc., and decide where they wish the device to operate. This is the load impedance that will be presented to the amplifier, and has nothing to do with attaining maximum power transfer, as it has made no reference whatsoever to the source's output impedance.