I don't know, I think pinch-to-zoom + pan is a pretty decent way of dealing with pages that have more complex layouts than basic document, but were designed using e.g. tables for layout. Given that most non-trivial pages would have been laid out that way back when mobile browsers were first coming out, it seems like a reasonable tradeoff to me.

That is to say, it's definitely a hack but I wouldn't call it useless, at least originally. These days it's a lot less useful since the number of pages that do benefit from this treatment has decreased dramatically. But at this point the die has been cast.