Hi SleepDeprived,
I haven’t heard of them before but the concept would be very similar to tension adjustable foundations (see the foundation post here) which can be used to create softer and firmer zones under a mattress and with a suitable mattress it can certainly be an effective way to help with sleeping posture and alignment … especially with body types that are more challenging to “fit” in terms of alignment. It would also have a similar effect to a zoned mattress (see post #11 here).
The difference is that they raise and lower the slats (by up to 12 cm or almost 5") rather than make them firmer or softer which would probably have an even more pronounced effect that could be “felt through” a thicker mattress than just using firmer or softer sections. It could also be a way to help with a mattress that had developed some soft spots or sagging in the mattress and would have a similar effect to some of the suggestions in post #4 here.
While the value of any idea or design always depends on making sure that the combination of support system and mattress is a good match for a specific person in terms of PPP in “real life” … the idea certainly has merit IMO.
Phoenix