Just want to point out all CDNs support HLS for on-demand assets. It’s just static http files. With HLS you just encode your file into multiple different nitrate files which are then split into small 5-10 second chunks and then wrapped in a text playlist for consumption. The protocol is still just static assets over http though.
Also of note: HLS supports byte range addressing, so you can create the various stream files as single .ts files rather than a collection of segments per stream. A client can use the Range HTTP header to select the window of bytes it wants for the stream/bandwidth slot it wants. This mode is supported from something like iOS 5 and up, and ffmpeg has flags to produce such streams.
If you want good cache hit ratios, you probably want to use segments as files rather than segments as byte ranges. Off the shelf http caching software tends to have filesize limits and may not cache large files in ram or even on disk if they're large enough, and may do unexpected things with range requests like request the whole file, then serve the range to the client. CDNs may be running totally custom http stacks or off the shelf stacks with tuned configs or somewhere in between, but if you intend to use one, it makes sense to build your content so it'll be easily cached.
BunnyCDN which the author is recommending does support the HLS protocol. What isn't stated is if there's any specific steps to achieve that.
You're right though, the author didn't factor this as a requirement to their needs.