Tree structure ? json, xml, protobuf, classes, functional programming, databases with foreign key, database internals, etc ?

Oh I forgot you also serialize and deserialize data - did you forget how that works ? Tree traversal again.

Do you know how organizationl hierarchy is structure ? It's a tree.

Do you know various maps and their usages ? We use them daily - it's very very important to know their internals. Hashing vs Trees vs Linked hash vs etc.

Google maps ? n-d trees ? Comparing data - merkel trees ? etc.

Every dev out there has common work with mine. But you won't be able to solve the problems that I face on a daily basis without thinking hard & without this dsa + concurrency knowledge.

Now, is it reasonable to ask these questions ? Heck yes.