As the name suggest, this is a endurance tyre meant to be used on long trips, day-in day-out.
The difference from regular Marathon is the added puncture protection.
Restated from official literature:
"Schwalbe's best selling model. The most puncture resistant pneumatic tire there is. In addition to the superior puncture protection it features many inner values:
Rolling resistance. The patented, 5 mm thick SmartGuard layer, when compared to all generic products, has a significant advantage in rolling resistance.
"Anti-aging" side wall. It now lasts much longer before developing unsightly cracks when subjected to use with too low air pressure. "