That's a very primitive approach. Once you're dealing with adaptive formats (DASH, HLS) containing multiple renditions (different bitrates) and/or codecs, it gets more complicated. I get that a single h264 codec/mp4 (webm) container file is easy enough as it is widely supported but once you're dealing with larger video's and getting them served over different connection types/speeds, it gets trickier. Atleast with services like Vimeo/YouTube, you don't have to bother too much.