The main usefulness of demonstrations is when they are used either to disrupt the power structure or to voice opposition to particular policies. The use of non-violent strategy as simply a way to draw attention to the brutality of a regime, thinking somehow that this will pressure the regime to abdicate, well, that is naïve to the point of recklessness.
Frankly, traditional non-violent strategy can only ever work in very particular contexts and conditions.
Targeting a company using mass demonstrations and civil disobedience-style activism can be a very effective way to disrupt operations and inflict short term profit loss. This can include sit-ins, picket lines, occupation of facilities and so on. You can halt all operations at the company for at least as long as your action continues.
Such campaigns have been effective in destroying investor confidence and causing share values to plummet, mostly because of damage to the company’s public profile. Actual operational disruption by means of civil disobedience actions is quite limited. It can be useful symbolically, however, and to heighten awareness about corporate power.