The difference that matters is where your layout is kept
Elementor keeps the design as structured data in a separate field attached to the post. Divi writes it into the body of the post itself. That sounds like an implementation detail and it is the single most consequential difference between them, because it decides what you are looking at on the day the builder is switched off — an empty page in one case, a page full of visible markup in the other. Neither outcome is good and they are not the same problem, which is why the answer to "can we leave later" differs by builder rather than being a general truth about builders.