Smoke grenades and shells not only hide you from the enemy's eyes, but also from their thermals!
With the spread of thermal imaging sights, the engineers of various countries came to a common conclusion: it was necessary to somehow hide the tank from the enemy behind smoke screens through which the vehicle could now be seen.
Three solutions became the most common: to use red phosphorus with aluminum particles, brass or graphite powder, or titanium dioxide and/or terephthalic acid particles in the composition of shells — aerosol smoke screens of such composition would be impervious to thermal imagers. But it is impossible to cram these chemicals into the engine smoke generator, so it does not protect from enemy thermals. Just like in the game!