How does that let a 800v+ Tesla i.e cybertuck charge at existing super chargers that are 400v? You wouldn't be able to charge anywhere that hadn't been upgraded yet, and while it might be cheaper in the long run to upgrade all super chargers to 800v+ capable than to make all high voltage Tesla's dual voltage capable, it would take years realistically to upgrade them (trained labor being the bottleneck), meanwhile you can't drive your shiny new Tesla anywhere beyond it's range.
If the cybertuck is higher voltage than existing superchargers, then they must choose either a DC to DC voltage doubler or ability to split the pack for series rather than parallel operation.
In that case, being able to split the pack is clearly superior, unless they can make a full power DC to DC doubler for really really cheap. I can't imagine a 300+ kW voltage doubler being cheaper or more mass efficient than a few more contactors and extra pyro fuse.
On the other hand, it would be neat if you had a DC to DC stage that was bidirectional and had a wide range of operation. Would provide a path to a interoperable v2h for those that want it, charging other vehicles that are stranded, or perhaps aren't cars (charge your e boat from your truck?), or hook up a string of DC output solar panels directly to the truck... But those are unreasonable features to expect.