In Southern African Air Law (R.S.A., Nam, Bots ...), you need an IR to operate away from base (50NM Radus) commercially if you do not have a certain number of commercial hours (I do not remember the amount, but I think it is 300hrs in commercial air transport, which a fresh pilot from flight school will not hold).
Mainly it is an insurance and safety thing, so that if you inadvertantly experience IMC, you will be able to get yourself and your passengers back into VMC safely.