Hyperlinks are a one-time annotation, and their presence does not change the underlying text. Stretchtext means a combinatorial explosion of possible readings - and if you've spent any time on the Internet you know you need to vet them all, or somebody will misquote you.
It still might be useful in an educational context, but even there I have my doubts. All the examples I'm aware of (e.g. http://tomasp.net/coeffects/ ) do, for me, not gain in clarity or readability.
There is an underlying idea about having text that is modified according to your ideas that sounds neat, but I haven't seen any practical execution yet that's particularly compelling. For educational text, the most potentially useful thing I've seen so far are is https://quantum.country/ which embeds spaced repetition.
It's a space that's ripe for a breakthrough. I'm curious to see what it'll be.