Resting bacterial spores are a beneficial differentiation for a bacterial population. Reducing the metabolic reactions to almost undetectable levels reduces the damage that could be caused by physical and chemical stressors (eg- chemicals, detergents, antibiotics, …).
Resting cells are quick and easy to form, without the high energy requirement that sporulation has. This makes minor stresses easier for the population to overcome as more cells can be converted to the vegetative state.