I truly believe that a back end needs to know about front end as much as a front end needs to know about back end.
And a more serious belief is that project managers / owners need to know about both. Thank you.

Why does the backend need to know it's consumers?
Or do you mean developers?

@dan-pud yes I mean developers

I'm not sure each discipline needs to know as much as the other. I like the concept of a T-shaped person where the vertical line represents deep knowledge or specialism and the horizontal is the broad knowledge of everything else needed to build and operate a product (yes I'm including DevOps tasks with this too).