How does white phosphorus work as a smoke grenade?

White phosphorus is too dangerous to use in any actual smoke grenade.

@kripter possibly true but that doesnt mean they don’t put it in there.

I imagine incendiary devices are designed to distribute the stuff over the target while smoke grenades keep the phosphorus contained within the body of the grenade and just releases smoke.

To answer the question about destroying vehicles in video games is – it’s a video game, they can make it do whatever they like but an unarmored light vehicle would likely not fair well.

You can read about it here: https://en.wikipedia.org/wiki/White_phosphorus_munitions

Incendiary devices use thermite, not phosphorus. They and smoke grenades are ignited by a standard grenade type 3 second fuse, minus a blasting cap.
In a situation where a smoke grenade is used to signal incoming helicopters to a landing zone, the phosphorus would create a fire danger to the helicopter, as well as creating a fire hazard in any dry brush.

Having now read more about white phosphorus (WP) than I probably should, I think I can provide a more definitive answer to the OP’s question. What the game is depicting is WP smoke grenades which happen to have an incendiary effect as an “unintentional” side effect. They cover the target area with WP which self ignites and produce smoke. It also can’t be extinguished with water, sticks to what ever it hits and inhalation of the smoke is particularly bad for you as well as burning . While as @kritiper points out you would want to use it to signal incoming helicopters etc it one of the most effective smoke screening agents available with the added advantage that it is also effective against thermal imaging which is why its use is still allowed despite the fact that it can be used as a chemical weapon and an incendiary both of which are banned under the Geneva convention. It has been used in every major conflict you care to mention since WW2 up to and including the action in Ukraine, often in such a manner that is questionable.

Interesting side note the M34 WP grenade has an area of effect (34 meters) greater than the range the average soldier is expected to be able to throw it (30 meters). So bve careful with those

@kritiper & @Lightlyseared, thanks for explaining the white phosphorus used as a weapon. So where would be white phosphorus allowed to fire? I know urban areas are discouraged with civilians hit and burned by WP.

Can you use WP grenade without burning someone?

Yes. If there aren’t any people where you throw it.

The purpose of a WP (or WP in general) grenade is to hurt people. Otherwise, one would employ a standard frag grenade, or anti personnel mortar round.