You could easily solve this the same way pull-out shelves all over solve it: a small lip or some other sort of securing. I don’t think that’s too much of a concern.

However it strikes me as a necessity for deep and rather badly organised fridges so while I can see the value (it’s pretty much the only not-useless thing I can see in the ad) it seems limited unless you’re at a pretty high level of use e.g. you use a literal ton of fridge space or you commonly need to swap entire shelves of e.g. desserts in and out.

Unsurprisingly slide out racks and trays seem pretty common on professional fridges.