Higher-kinded types themselves, not necessarily, but the abstractions they afford are, once you've gotten used to them, a huge time saver.

I've gotten used to handling concurrency as a monad, for example, and honestly dread the time when I have to manually deal with manual synchronisation again.

Companies are made of people, and the people writing the code certainly do, IME. (In some companies that will have little bearing on the company's decisionmaking, but I view that as an indictment of those companies' processes). It's not something that immediately jumps out, but having written code for a while with higher-kinded types available, it would be horrible to have to expand that out into cases.

It just seems weird that this feature would stand out when compared to everything else Scala has to offer.

There are plenty of features in Scala that I couldn't live without, but most of them are features that I could find in other languages (e.g. Ceylon, F#). Higher-kinded types are the big "blocker" that really keeps me Scala-only.