Status values of the units
These values are the base values of the units, i.e. they have to be multiplied by the individual bonuses.
In the case of artillery, one cannot say in general "the higher the level, the better the unit". For example, the T9 artillery has a higher attack power than the T10 artillery. In return, however, this has a significantly higher loading capacity.
The attacking power of the infantry is significantly lower than that of the other units, so they should be left at home during attacks without resistance, for example when fighting the werewolf on Saturday or at the underworld gate.
The attack power of the artillery is usually higher than the equivalent cavalry or distance units, but the bonus values of the gems are often not for the artillery, so it is preferable to leave them at home. In addition, the artillery is always slower, which increases the march time.
To make this clear a few sample values from the fight against a level 5 wolf (Saturday event):
As you can see, infantry and artillery do significantly less damage than ranged and cavalry. Infantry has a lower base damage, which is not compensated by the damage bonus. Artillery units have a higher base damage, but most gems lack the necessary attack bonuses.
For this reason, a distance unit of a lower level of a cavalry unit is often preferable in an attack, at least if the damage bonus is almost the same.