I have been using such "expeditionary forces" as raiding parties in my Romani campaign with great success. The world has basically been reduced to me against the Yellow Death (with the Baktrians doing their thing undisturbed in the far East), so I have decided to embark on a rather vicious scorched earth policy against Ptolemaic settlements around the length of the eastern Mediterranean -- from Side to Paraitonion. To do this more easily, I first established bases in Cypus and Augila, and will soon establish a better-protected settlement in Kyrene. I am blockading all Ptolemaic ports in the eastern Med and have burned four major settlements (Side, Tarsos, Sidon and Paraitonion) to the ground. In the battle for Augila, I have also effectively wiped out three full armies of the Pharaoh. I don't really need the cash -- remember, this is a Romani campaign -- I just want to put a serious hurt on the Ptolemaics in preparation for a more serious expansion in the near future.

It's an interesting and enjoyable (heh-heh-heh) addition to the game!