I totally agree with you on this. It was a little shocking to see the deep cuts into the mat. I was also annoyed that you really do have to get different mats. The wide dies need the same size mats. The skinnier dies need matching mats. I kind of think that when you buy a new die the mat should come with it.
Anybody getting a Go might find the information useful. The cost of replacement mats should be figured into the cost of using the Go.