The stuff is dense. Dense stuff penetrates or breaks less dense stuff more betterer.
You can derive this, even if you know nothing about it, from its use - "Armour piercing Projectiles". Stuff that needs to go through other stuff
must be is more effective if more dense than the other stuff it needs to go through. You'd expect the people who do this for a living to use the densest stuff they have.
They aren't coated, they use a solid block of the stuff.
It can be incendiary.
Now they just need to use depleted uranium as armour, but I expect this would have massive weight disadvantages. You could probably achieve a similar effect by raking the armour even more.
* edit: "Armor plate - Because of its high density, depleted uranium can also be used in tank armor..."
This:
en.wikipedia.org/wiki/Depleted_uraniumPersonally I wouldn't be sprinkling the stuff on my Weeties, but as most of us agree there is already so much dangerous radiation floating around a few of these shells scattered around Australia are negligible, at worst.
I'd be far, far, far more worried about the state of the reefs where the (bastard) French conducted their nuclear tests. Will they leak?
^ Punch a hole in the armour first, then go boom! Aren't the humans lovely?