It isn't like X is yet using LNG, E-Class pax routinely complain about soot when staying in aft staterooms. While no doubt each and every tiny fuel-reducing incremental or "drop in the bucket" change is indeed good for the planet, nearly all large ships including cargo are notoriously dirty.
Also, none of the E-Class suites offer any kind of IV, they all offer traditional balconies. Certainly feels like they leave the fuel saving IVs for us peasants