Half a canoe is worth less than no canoe at all.
On the other hand, eating half a pear is much better than not having one. You might get 85% of the value from only part of the pear.
Some projects only benefit us when they’re finished all the way. Knowing this in advance is a useful strategy. For example, an ad campaign with a budget half of what it should have been, or an almost complete social media promotion does nothing much at all except help the media companies.
It’s possible to be productive and create value with halfway projects. The trap is treating an all-the-way project (like a canoe) as if halfway is enough.