on Large Units setting:

Velites upkeep is 170 denari. Too expensive for what they do.

Wardog upkeep is only 50. Two turns to build.

Town Watch cost only 150 denari and 100 upkeep. So they are a great fodder supplement to the Hastati/Principes backbone. Nobody uses them?

Principes last a little longer than Hastati especially against the tough Cavalry like the Numidian Cavalry the Carthaginians hire.