I'd agree with this but also add that it's important to know the benefits of each algorithm compared to others in the same class (i.e. when you'd use each sorting algorithm).

It also helps to be able to adapt an algorithm when the vanilla version doesn't quite cover what you need. I don't think I've ever had to implement a well-known algorithm from scratch at work - I'd just use a library for that and spend my time focusing on business logic.