Butter temperature showdown: cold cubed vs melted for scones

Last Saturday I baked two batches of blueberry scones back to back, same recipe from my go-to cookbook, only difference was how I handled the butter. Batch one used cold butter cut into little cubes and I worked it in with my fingers like the book said. Batch two used melted butter that I just stirred into the flour mixture because I was impatient and tired of cold hands. The cold butter scones came out tall and flaky with those nice layers inside, while the melted butter ones spread flat and turned out dense and almost greasy tasting. It took about 15 extra minutes to cube and rub in the cold butter, but the texture difference was huge. I always thought melted butter would save me time without hurting anything, but now I see why recipes are so picky about this step. Has anyone else done a head to head test like this with butter or another ingredient and found the extra effort actually matters that much?