Becoming a Canadian citizen gives you additional rights, benefits and protections that are not available to Permanent Residents, including the right to vote and the right to hold public office. Citizens are no longer required to meet residency and other requirements of Permanent Residents.
There are many differences between Canada Permanent Residents and Canadian Citizenship. PRs who do not become citizens are not entitled to the same rights and privileges as citizens. Penalties for committing a crime in Canada for citizens are different from permanent residents and temporary residents - including permanent deportation from Canada.