Smoke grenades are cool and can be useful in some situations, such as masking movement, etc.
But even then it's not always effective. Ever see The History Channel program about the battle for Hue City in Vietnam? Those Marines were talking about how they had to "adapt" and "improvise". They had been taught to toss smoke grenades before crossing streets. But they were taking heavy, heavy fire as well as casualties by doing so.
So they thought up another solution and they moved in one of those big ass recoiless rifle (4 barrels on a chassis) and when they were prepared to cross, they set that sucker off down the street. Not only did it create a lot of smoke and dust of it's own, it gave the enemy something to think about other than just shooting at the smoke.
But yeah, smokers are cool. The fact I have none would make me interested in a couple. But I'm just not sure their actual value and use would be worth $35 each.