I think the more we touch, play and feel, the more we can learn. With hands-on activities, we can reach deeper levels of understanding of abstract concepts such as numbers.
This methodology is a good way to engage our students and keep them motivated (given the fun these activities imply and the fact of giving kids an active role from the beginning) .

Besides, Maths are everywhere in our life (making a cake, read a map... anything), so it's very easy to prove why it is important to learn this subject. If we have motivated students who also have a purpose, a reason to learn, we will be unstoppable!

Last, but no least: hands-on activities can help improve understanding of those children with special needs, reducing the pressure and the feeling of being stuck, left behind while the rest of the classmates progress.

We need to adapt to society, to our students and their needs, so we cannot keep teaching Maths the same way they've been taught since... always?

Also, to include hands-on activities in our daily Math-lesson practice, we need to be careful and thoughtful. We need to reflect about what we need to teach, create a "storage" of hands-on activities and resources and design a plan telling what will we do, what for, when and how. Otherwise, we might fall into an empty practice, just playing.

This work obviously requires a fair amount of time... and I don't know what it is like in your schools, but sometimes we feel overloaded with bureaucracy, which doesn't facilitate either the change of mind or the strategy desing.