Perhaps this is obvious but the answer is: cost. Developers are expensive. Delivering a viable poc cheaper, sooner, even if you end up having to redo it all anyway, can be an excellent trade off.
Wonder if there will be similar businesses and freelancers who will start to specialize in the migration from no-code to code in the same way that there are for on-prem to cloud.
Interesting thought. I was also thinking it could be good if you could reify your no-code solution into some sort of generated code, as an escape hatch. I suppose the trick is generating something vaguely sensible.