To be fair the author acknowledges this. To make an analogy, this seems to me more like the equivalent of ASM than the equivalent of C, the only reasonable way to make this work is to have a high-level language that "compiles down" to Hope.
I'm not sure I agree with this premise either, the hierarchical structure seems inherently semantical to me, but the argument of the OP is it isn't the case.
> what's the point of making it a text format at all?
The text part is ASCII, so it make sense to represent it as such. The "presentation" part could be binary.
As for the text part, that is simple. I like to be able to manipulate text as text. There are many many tools to work with plain text. I can use regular expressions to search through text, get ranges of the result and apply an annotation to those ranges. You lose a lot of that in any other format.