I'm not a scientist and I'm the wrong kind of engineer, but I suspect while good people can improve brain protection, they'll never stop concussions when big fast men collide in the open field.
That doesn't mean they can't mitigate the effects and they'll need research and data to do so. IllegalContact has a point in saying that the measurements will always be imperfect and often be misleading. Neuronet has an equally valid point in saying (if I may broadly overinterpret) that getting a large volume of data over time allows us to draw conclusions in the aggregate even as individual measurements are suspect.
What we don't know now is where the research will lead. Diagnostics may not be revelatory for dozens of years until there are symptoms or even autopsies; that's when we'll need the retrospective data. We can ignore flawed data if we want, but we can't reach back in time and get what we didn't record.
And when they start making changes, probably first at the high-school & college level, to helmets, artificial turf, training & coaching, rules and other factors, the measurements will help them analyze the effects even over short periods of a year or two.
Which is why I'm hugely disappointed that the NFL stopped helmet sensors. But not surprised. They are tobacco.