Personally, I do not think it is a deterrent for tourist arrivals. Most people would likely either not know in advance or be used to it from their origin/transit points. On the contrary it could help showcase the country as taking public health seriously by discouraging smoking.

I always find that you are being hit by a wall of stinky smoke when forced to walk past those smoking rooms - as soon as the door is opened the smoke pours out and lingers in the air for long.