Only if you stick the smoke and place the grenade perfectly, else it's very easy to avoid... For example, if you double jump or glide or what ever as you are getting smoked, you continue to travel out of the area... It's pretty easy to avoid. Firebolt grenade with proper perks is still the best grenade by far, and it's due to the length of time you put someone out of play due to the dot that remains. But that's coming from a class who is supposed to be "magical", so what's the problem... You adapt.