I used this strategy with one of my students who was finding multiplying TU x TU using the compact method confusing. It really helped him to understand what to do. In fact, we only used the method a few times before he felt confident enough to use the more conventional method.
Another student was having a similar difficulty. I showed her the method and we discussed it together. That conversation enabled her to complete multiplication sums without the need to draw the shapes and colour code the numbers. The conversation was enough.