This is being advertised as an after school reading and math program that allows kids to either consolidate knowledge or accelerate learning. There's no reason I know why it couldn't be used as a part of a homeschooling program. After School Math & Reading Programs - Kumon
these kinds of tutoring programs cost a fortune. It would probably be cheaper to hire a homeschool teacher for a subject to come to your home.
Kumon started in Japan where there is a rigorous (and expensive) network of afterschool programs. In Japan they even cover how to properly use an abacus (soroban (算盤, そろばん) with insanely high speed precision (my sister-in-law can still blast across those beads, I was speechless). In the US they cater to mostly upper middle to wealthy families and by nature are very, very expensive. Jennifer is right there are many less expensive ways to cover the same material.