Don't know why we practise Canberra approaches when we fly out of YMMB.
That is an easy question. The flying school makes more money from you flying all the way to Canberra and back. With slight variations all ILS are basically the same so EN or AV are all you need to practice on. If the flying school wants you to practice at Canberra for whatever altruistic reasons then tell them you want to do it in a simulator or synthetic trainer. Saves a lot of money and is just as effective.