I have to disagree with their claims of better weighting the front wheel. The longer front center results ina weight distribution that is closer to the rear wheel than the front… so front wheel weighting is actually reduced for same cockpit geometry. If also taking into acount the higher stack height, then this further moves your weight back. So personally I would say that was a false advertising claim.
The slight increase in stability is true, but the potential downside to that is that the longer wheelbase will result in a slightly less nimble handling.
I also wonder about the ergonomics of this on long days riding in the saddle. If you imagine your arms have a set length (I know this is not true for riding generally, but for long gentle non technical climbs it is not uncommon for people to ride with pretty straight arms), now imagine what it is like to gently steer with a regular 50-70mm all mountain stem, and with a 10mm stem, focusing on how your shoulders have to move, and how that will affect stability and comfort. You make the call on that aspect.