Volume is the least useful of the three signals it produces. Cost per click tells you what competitors are willing to pay for the intent, which is the closest thing to an objective measure of commercial value; the shape of the SERP tells you whether you can win it at all; and your own Search Console impressions tell you what you are already eligible for. A keyword plan built on volume alone reliably produces traffic that does not convert.
Grouping matters more than collecting. A modern page ranks for hundreds of variants, so the deliverable is not a spreadsheet of ten thousand keywords but a map of intents to URLs. That map is what prevents cannibalisation, sizes the content programme honestly and makes internal linking obvious.