He’s saying practise is realisation, which is a concept developed by Dogen, the founder of Soto Zen

that’s not what the story says. in any case, the point is to explain, in terms of dualistic if-then logic, that the if (you practice now) and then (you will wake up) are a single non-dual thing. but to communicate in in terms which make sense to the dual, if-then mind, one needs to use dualistic language.

I imagine he would say to practice is to realize and to realize is to practice.

Isn't it just saying, a gain realized from compound interest over long-enough time is crazy yet short term gains is practically zero, yet total gain is anything but zero, and also there really isn't a magical zero effort quick and easy jackpot skill gain IRL

It isn't. Because when they put it much more sensuous & yet concrete terms, than the one of numbers & cents, the reader's mind might be primed to apply the idea to more general problems if & whenever they do arise, such as the problem of finding the right problem to solve.