Yes, scoring as high as possible is better, but not an "absolute" requirement, for Canada.
Please note, IELTS scores for Canada are not like they are in Australia, where one only gets "meaningful" points for IELTS if they either have 7 across the board, or 8 across the board.
Meaning, one can get a max of 28 points (according to old points system). Scoring 8 7 7 7 does not seem to be an "absolute" requirement.
With my score of 7 across the board, I believe I can secure 21 out of those 28 points. Which should be more than enough for me.
Despite my rant, everyone's mileage/experience is different, so yes, scoring as high as possible is good. Yet, not everyone can "afford" spending Rs. 20,000 per attempt in the pursuit of improving their IELTS scores to CLB9 or above.