Artillery is a niche purchase, mainly because it generally compares unfavorably to an infantry and tank mix. Artillery paired with infantry provide the greatest attack/cost ratio of any unit.
The major drawbacks are:
1.Artillery has the worst defense/cost ratio of the 3 units.
2. Artillery also only projects the threat of deadzones one territory away instead of 2 for tanks
3. Artillery attack ratio drops to 0.5 (below a tank) once infantry are exhausted.
Artillery definitely have a place in purchasing, where these drawbacks are mitigated. Ignoring artillery completely is a mistake.
Prime examples I can think of:
1. UK amphibious landings. The battles usually conclude in 1-2 rounds with all UK land units dying or taking the territory in a dead zone. Artillery provide the same offensive punch as a tank at 1 less cost. Transport provide the mobility to project the artillery’s threat of deadzoning the same range of german territories as a tank.
2. Germany or Russia situations where land offense is needed to trade Caucasus or Italy. This is the case when the country is forced back to the capital and only a couple territories. It’s critical to continue trading these territories as long as possible, or losing the capital is further accelerated. In this situation, you only need to project the deadzone one territory out and provides the most offense for least cost.
3. Early R1-R2 buys for USA. It’s a priority for the USA to remove the axis from africa. Buying art in early R1-R2 rounds, then tanks later in R2-R4 rounds maximized the pressure on egypt on R5-R6.
4. When a country has a leftover 1 IPC and wants some offense.
attack/cost:
infantry - 0.3333
tank - 0.6
artillery - 0.75
defense/cost:
artillery - 0.5
tank - 0.6
infantry - 0.66
Note1: i’m aware that hits/cost ratio also matters, but analyzing it quantitatively is complicated. It’s fair to discount the tank and art ratios a little to reflect the differences in hits.