> I missing something but aside form the gradient capability I didn't see much advantage presented here.

* You can re-use existing carriages without having to seal them hermetically.

* You don't have to build a sealed tube for humans: No emergency exits every mile or so, no airlocks at stations except for maintenance access.

* Because the system seems to be just as wide as the tracks, existing tracks could step-by-step be retrofitted.

* Give the construction crew a few extra bucks to put some fibres in there ;)