Let's say you are trained and experienced in bank teller job. We can safely say you are a skilled worker as you have the skills to perform banking transactions. If a bank employs you as a teller, they do not have to train you and you can quickly start on the job.
However, being skilled only means that you can start on the job immediately and the company saves cost on training. It doesn't lead to productivity growth.
If you perform as fast as the others, productivity stays the same. If you perform slower than the others, productivity actually goes down. A skilled worker does not necessarily translate into higher productivity.
There is productivity growth only if you are able to serve more customers in a shorter time than the others. Another factor that has to remain constant is the other tellers have to at least maintain their current level of productivity.
But if you are able to add value to the bank by proposing new banking procedures to cut down manpower requirement, up selling your other services, providing exceptional service and build trust to customers, it is a different story.
Go for people who can add value, not just skilled.