I guess you could also use the sims to do calculations on an attack one might actually launch, to see what units generate a better result.
Examples: Attacker: 5 Inf, 5 Art, 3 Fig, 1 Bom. v. Defender: 10 Inf, 2 Arm.
Attacker: 5 Inf, 4 Arm, 3 Fig, 1 Bom. v. Defender: 10 Inf, 2 Arm.
In this example, we see that the first attack with 5 Art has a 90% survival rate, while the same attack with 4 Arm instead has an 82% survival rate. However, to illustrate my point about mobility: if you have been building all Art, what you’ve got for the attack is what’s in the territory. That’s easy for the enemy to see and to prepare against. But if you have some Armor floating around the back, you can add more.
Suppose just 2 more Arm are in range. Throw these into the attack and suddenly you have a 98% survival rate. With artillery that’s just not an option.
The reason D-Day worked is that the Germans didn’t know where the Allies would land - so they had to spread out their coastal defences. Having a bunch of Armor does the same thing - you could potentially strike a number of places, so the enemy has to choose between spreading out their defence, or selecting a few territories to just sacrifice.
Tanks add a huge dynamic element and introduce a lot of tactics. It’s a completely different war if the enemy isn’t sure where you’ll attack. If you have 5 Art in the Balkans, they can hit Ukraine and that’s about it, and the enemy knows it. If you have 4 Armor there, they also have the option of hitting Karelia. And some opponents might not realize that your tanks in the Balkans and your Infantry in Germany (with baltic transports) and your tanks in Germany and Ukraine can all hit Karelia. You might have a defensive force in Eastern Europe that they’re not so worried about, but add in all that other stuff and you can rout them.
Sure, the Allies might take EE and Ukraine from you, but if you kill 50 IPCs of gear in Karelia for a cost of only 18 IPCs yourself, those few IPC territories are nothing in comparison - especially as your tanks can swoop back down from Karelia to retake Ukraine or whatever and kill whatever the hapless allies happened to put in their, thinking you were now way far away up north.