Yeti were a bit late to the ebike game with the 160E, having spent time developing a linkage specifically for ebikes with Sixfinity.
Sixfinity has different kinematics, specifically designed to deal with the added weight and speed of ebikes. The linkage provides less anti-squat and anti-rise. The progression rate can be adjusted between 25 and 35%, changing the feel of the bike or helping the shock work with coil shocks.
Another advantage of developing a linkage specifically for ebikes is that Yetis have been able to keep the chain stays at a fairly short size, even with 29" wheels.
Internally routed cables with secure entry and exit points.
Uninterrupted seat tube allows the use of longer dropper posts.