Commercial-grade applications need some grade of offline operativity that classic HATEOAS can't provide, often target users who won't learn or can't really use a web browser (tabs, back button, extensions, bookmarks besides whatever they can fit in the bar, etc), often want to give a UX which abuses and deforms a web browser by design. Yeah, FE engineers may all look like dumbasses with macbooks (i don't think this of them!), but they have real problems to solve.