If a transceiver has an in built automatic antenna tuning and matching
unit, is there any point in measuring the VSWR as a way of ascertaining
its performance?

Obviously this would be measured with a thru line meter which would be
placed in the feeder system. However, I have been thinking and it
would appear that the tuning and matching unit would become part of the
antennas impedance (its late and I hope that makes sense).

The reason I ask is because I am trying to find out how well certain
transceivers will perform with antennas which are designed for
different systems.