A MTB Full Suspension E-Bike has suspension at both the front (fork) and rear (shock). Ultimately the bike will soak up the terrain making for an easier, better handling and more comfortable off road bike. A full suspension bike is easier to ride because it's doing a lot more of the work soaking up off road terrain, instead of you - the rider, leading to a more comfortable ride and thus you should be able to sustain a longer duration of riding.
Let's not forget that most of our full suspension models also have the opportunity to lock the rear shock, effectively turning the bike into a hard tail. Great if you wish to commute in the week, then unlock the rear end ready for some off road fun at the weekend - effectively two bikes in one!