How on earth having an unknown, unsecure, unreviewed binary blob running on your computer be "the more secure method"? Compared to what? But having a blob in the browser running in a sea of proprietary code (MacOS), I don't think it makes such a big difference.

"a more secure ... non-DRM video source" - more secure compared to what? What does security means to you? If you are going to watch non-DRMed video, it's already as secure as it can get, all you need for the efficiency part is better codecs, think of VP9, or Daala.