That line is not always certain and witholding labour may often be the only recourse the workers have. Whilst I'd prefer the unions use their hard won rights more carefully I wouldn't wish to remove them fully.
There is always mutual benefit, whether it's enough benefit for you is a different matter, as is whether certain aspects (such as hours) are high or low on the benefits list
For instance it has been an extremely long time since any of the Electricity or Water industry unions last took action but the Postal Workers seem to strike repeatedly. They are driving their jobs out of existence with their action in my opinion. How is that beneficial?
Its not beneficial in any way, the sooner the more militant unions learn this the better.