Depending on what you think your future holds, the disadvantage of becoming a us citizen is that a Canadian would now have to file a US tax return every year for the rest of their life.Canada does not require such a return unless you are living here. (Which is the answer to your first questions)
If all of your income is derived for US source and you don't think that will change, it MIGHT be more convenient, to give up the Canadian citizenship
But in this expert's professional opinion, you are (1) closing the door on any options that MAY arise from having your Canadian Citizenship and (2) subjecting yourself to that US tax rule that says US citizens ay taxes on all worldwide income, regardless of where you reside
If you are a U.S. citizen or resident alien, the rules for filing income, estate, and gift tax returns and paying estimated tax are generally the same whether you are in the United States or abroad. Your worldwide income is subject to U.S. income tax, regardless of where you reside.
As I said earlier, Canada does not force you to file a Canadian Tax return unless you reside there ... This is one of the primary examples of Canada's system being more forgiving generally