If I calculate the dimension of the matrix after `NumberForm` directly, then there will be something wrong

    test = NumberForm[IdentityMatrix[2], 2];
    test // Dimensions
    (*output {2}, but {2,2} is expected*)

If I show the result of `NumberForm` and then calculate the dimension, the result is right

    {{"1","0"},{"0","1"}} //Dimensions
    (*ouput {2,2}*)

What causes this? Is it a bug?