But right now as a programmer, I am using data-structures more on an as-needed basis. Sometimes it is difficult to find the right data-structures for the job. So then it would be nice to have a resource that provides the functionality of data-structures as a black box. Learning these would make more sense than learning also all of the gory technical details upfront.
Even if you already have and are happy with CLRS, Skiena's book is a great addition to your library.
But when you need more, it's good to know your options.
In fact I'd say nobody can afford to be intimately familiar with all the various advanced data structures. But most people will, at most, just need to know the things they might need, then go learn about them when they need it, and many won't even need that much.
(Note that is a correct usage of the O notation; because of the fact that those two things are equal we generally just use O(n) because for clarity you might as well use the simplest member of the equivalence class defined by the O notation, but it is still valid to write O(n/10). It's just an error to treat it as anything other than equal to O(n).)