What is hprot[3] - modifiable attribute in AHB5 spec? what is the significance of it ? Please share usecase.

I just couldnt find the significance of it . This attribute comes with lot of restriction, transaction whould not be split, hsize should be retained etc.
but why ? what is the actual impact ? what if we spit the transaction or hsize is changed ?
Please point to a document if any which explains this topic in detail.
-Thanks,