Due to certain structures of online learning, some users may find it difficult not being in a hands on class session. For instance, say you’re in a tech theater class discussing the creation of wooden platforms for actors, if you aren’t physically there- rather looking at textbooks and presentations online- you may not fully understand dimensions, processes, and other aspects specific to your teachers in -person criterion.
Also, with sites such as Khan Academy and Edementum, they teach a curriculum that may be slightly skewed from what your peers are learning in an irl setting. Thus, potentially putting you behind.
All of this, however, depends on the type of student. Everyone has their own way of learning.