A spark cannot propell a 2,000# 16" shell 20 miles and create a massive explosion at the far end. A spark, IS, however what ignites the cordite that pushes the shell out of the gun at such enormous speed.
Of course Luther didn’t create the Reformation by himself. The situation in the late 15th century was a massive loaded gun. But he WAS the spark. And that IS significant. Luther’s theories had a gigantic effect on the theology of those who split off from Rome that continues to this day. Of course there were others: Calvin, Zwinglee (sp??), etc. And it all may have been squashed like so many before if not for the Islamic invasion on the other side of Christendom.
And I still don’t believe it is a cheap shot to say that Luther suffered scrupulosity. If you are familiar with the problem, his writings and behavior practically SCREAM it.
Try “How the Reformation Happened” by Hillaire Belloc. Excellent reading.