What you describe are relatively niche or uncommon uses of these algorithms and data structures. Further, the specific implementation details of a given algorithm become relevant in these contexts. Different implementations of a hashtable can lead to substantially different operational performance, and no textbook understanding (including the toy implementations performed as part of a CS curriculum, for example) of what a hashtable is will lead to the kind of understanding you discuss.
Of course. That’s why good libraries will describe the specific implementation. Not just hash table but whether or not there’s open or closed addressing, how buckets are chosen (eg cuckoo hashing, Robin Hood, etc). A text book implementation is simply meant to give you a starting point understanding of the design space but you need continuing education to become more of an expert to understand when this stuff matters. But this expertise is valuable across problem domains and levels up your technical expertise. At my level all the engineers I’ve ever interacted with have a solid grounding in the fundamentals.
