What’s the deal with flywheel inertia?

Does flywheel inertia really matter? I’ve read conflicting information on this forum and others that it does/doesn’t make a difference. GP Lama made a video saying the muscles will engage at different points in the pedal stroke depending on the relative speed of the flywheel. I, like all of us using TR want to maximize fitness gains… I’m so scared I’m missing out on potoential benefits I will alternate between the big ring and the small ring for my insterval sets so I can evenly distribute my time spent at “high” and “low” flywheel speed. Am I just wasting my time and wearing out two chainrings in the process? Or are there real benefits to be made?