In my experience with 1:1 before and during my Masters in Education, nothing could compare to the learning and growth my students had from that highly personalized (and personal) instruction.

It's super common for students to not understand material or express that they don't, but it's just not possible to drill into each specific student's particular knowledge or skill level in the classroom environment.

On the social and behavioral side, many students who struggle in a classroom environment transform into model students when taught with both the care and privacy of 1:1.

For me, I feel it's a combination of hyper-personalized instruction plus compassion in a relationship where it feels safer for the student to accept the value of improving at something without social pressure or embarrassment.