I mean, from a technical on-paper perspective this is probably an achievement. Possibly a chance to make use of binned dies and not waste chips, and a chance for manufacturers to fit machines with the amount of RAM they intend.
From a commercial prospect however, I look to my reseller/box-shifter needing to hold multiple variants of a "lifespan commodity" and them likely feeling increased risk in doing so. Combining with the physical cost of stocking additional lines, I expect not only no saving here, but perhaps a cost bump to the average end-consumer in reality, if these off-size DIMMs ever actually make it to the consumer market?