CBM makes longspearmen map move 2, which might give them a niche. (Though CBM is kind of mean to Eriu. Their longspearmen have the exact stats but only map move 1) The long-spear can be kind of good during expansion since it allows them to repel ordinary spears. The axemen simply looks really inferior to the tower guards, or almost any unit really.
That the way in dominions, sometimes units are added for flavour and not for their usefulness
