You built the workflow, then you found the field was empty.
A vendor quotes an accuracy figure for the whole dataset, and it sounds strong enough to move on. So you sign, you build, and a month later you discover the one field your workflow actually depends on is populated a third of the time. That happens because a blended accuracy number hides the thing you needed to know.
Some fields fill in almost every time. Others rarely do. Averaging them produces a number that is technically accurate and practically useless. We publish fill rates field by field, on every dataset page, before you talk to anyone.
Email is 23 percent globally and 41 percent in the US, and that is what we print, because that is what it is. You can look at that, decide it does not clear the bar for your use case, and walk away. We would rather that happen now than after you have shipped something on top of it.