The ease of use, flexibility to configure it for my specific needs (as well as others).
It's always been easy enough that I can get someone else in IT or another department who knows nothing about computers/programming etc., but is able to easily set up what they need using only their own knowledge with no programming required from me at all! There are several modules available which make creating custom trainings much easier than having just one platform where you have to create everything yourself if there isn't already something suitable out-of-the box. Also being hosted by an organisation like Microsoft makes things even better because we know our data will be safe against any future breaches - so this gives us peace of mind too when working remotely sometimes without direct oversight over security issues such as these.