WELL, As my own views, two mains disadvantages of online learning are :
-lack of motivation for those of students who hate working /or we appreciate less, hard working.
-no follow up, of the students unless when involves himself in asking questions or, dark points.
advantages related to could be in first cost savings, so students no need to travel abroad.
another point could be a self-esteem and autonomy that make students relying on themselves.