New, rare or unreliable equipment

[Ts4EVER]

Not to mention that often in games with rarity rules, the effect is that you can buy fewer of that equipment in battle. Most rare equipment was rare in the sense that only a few units had them, but these units were generally equipped with a lot of them (some exceptions like the Sturer Emil of course).
Overall the Jagdtiger might have been rare, but in some battles, like parts of Operation Nordwind or the Ruhr Pocket, they were quite common. Rarity rules destroy that kind of thing.