That may be the point, but I have to say that workers/unions who engage in deliberate work slowdowns (sick-outs, work-to-rule, etc.) end up doing nothing more than shooting themselves in the foot. If the point is to get customers to take their business elsewhere, they should give the customer prior notice of that fact, so that the customer can do so without being severely inconvenienced.

A strike is something very specific... it is (in an ideal world) a last resort when negotiations have reached an impasse and shows that the workers are willing to put a complete halt to service/production, possibly lose wages, etc. in order to negotiate for the terms they desire. It shows commitment and fortitude on the part of the workers where they are willing to essentially sacrifice their jobs in order to get what they feel they're entitled to. Moreover, a strike involves a complete work stoppage; customers know what to expect, they know they will be inconvenienced, and they can plan accordingly by taking their business elsewhere beforehand.

On the other hand, a work slowdown or a sick-out has a much larger negative impact on the customer, because they're not expecting it and are essentially blindsided. The customers expect business as usual and therefore do not plan in advance to take their business elsewhere. Instead, they receive deliberately poor service and, by the time they figure it out, it's too late. Moreover, because a slowdown usually does not involve the same press attention and customer communication that an organized strike involves, the customer is unaware that the slowdown is supposed to be a "message" to management... instead, they end up blaming the workers because they are the customer-facing employees. In the end, the customer who "takes his business elsewhere" because of a work slowdown is likely so angry that they'll never return, even after the work slowdown is over, and that's just as bad for the workers as it is for management.

An organized strike is much more preferable from a customer perspective because they know why it's happening and can plan for it in advance; it's also preferable from a worker perspective since it shows their resolve and has a chance of gathering sympathy from the customers. On the other hand, a work slowdown is essentially nothing more than a gigantic middle finger that's intended for management but ends up flipping off the customers instead, because the fact that work is going on at all presents the expectation of "business as usual," and when that doesn't happen, it's the customers who suffer.

What's the point? No work is better than shoddy work. Either do the job properly or go on strike; anything in between does nothing more than hurt the customers who (indirectly) pay the workers' salaries. Such juvenile tactics garner zero sympathy.