Discovering of Value Added Employee

I went to a famous old time coffee shop for tea break while waiting for cash wash this evening.

I guess this coffee shop has about minimum 20 to 30 foreign waitors and they are required to wear uniform during working. One of them somehow in casual wear and I found out he is actually on leave today.

What surprised me is that, he served the customers whenever available, while spending his free time to sit down to talk to customer, go out direct car traffics, and walk around. Is this what we called value added employee?

Perhaps he has nothing to do during that period, but he still help the boss to serve the customers during his leave. There's definitely no extra pay for that. How many of us willing to do so? Is it what we called value added employee?

I believe most of the bosses would like this kind of employee. Not only because the extra hard works, but it is more like contributing as one of the family members, trying to help whenever possible. 

If this kind of spirit exists in a company, I strongly believe the company can do better than others, have the bigger possibility to attract more customers and obtain more revenues, and eventually, the boss can distribute bigger bonuses to the employees under normal circumstances.