Probably just because it's been the most popular way to use tobacco for a long time. Some places in the US I would argue snuff is more popular. Cigars aren't supposed to be inhaled, they're more for the taste.
I use dry rolling tobacco wrapped in a paper towel and don't chew just sit there . Smoking delivers small amounts of nicotine instantly causing a very strong conditioning stimulus reward. Dip acts over like a hour so it's stimulus one hour later . .. reward
Extremely aggressive marketing for almost two centuries? Or being extremely inexpensive at one time? Or for an extremely long time people thought they were good for you and healthy?
Its an easy, quick hit for those basically hooked on nicotine.
The other avenues of tobacco, like cigars and pipe tobacco, are more an appreciation/marveling of the product and the work that went into making it. The essence of tobacco, if you will.