Lets get the first basic concept clear. A lawyer is a legal servant of the society who has expertise in understanding the constitution and the laws of Canada. They have experience and in depth knowledge of how to tackle any legal issue and hence are an important member of the society. There are many reasons why you should hire a lawyer to fight for your case instead.
Understands your situation: A lawyer will carefully listen and asses your case to see if you have good chance of winning the case.
Represents you: Your lawyer will represent you at every stage of the case and will speak on your behalf.
Legal knowledge: All lawyers have the right knowledge to fight your case if it goes to trial. Fighting your own case has big chance of losing with a little to know legal knowledge.