They're useful, but I could never see them replacing small-group teaching (1 PhD student/faculty member to 2-3 students), a standard feature of my university. I

They're useful, but I could never see them replacing small-group teaching (1 PhD student/faculty member to 2-3 students), a standard feature of my university. It lets them focus on exactly what _you_ need at that time, and can pick up on weaknesses and misunderstandings you might not have even realised yourself.