Watch this video on YouTube.
stevygee1987, one of those great WP YouTube Lyte users, discovered that somewhere along the way audio-only embeds stopped working on mobile (iOS & Android). The root-cause of the problem is that for mobile browsers YouTube does not show the bottom controls any more, even if specifically requested to do so via the iFrame API. I’m waiting on some bright soul to provide me with a good solution (on stackoverflow, so your upvote might help), but as a temporary workaround audio-only on mobile will be rendered as a normal YouTube video (which YouTube prefers, really, you should not do audio-only if you want to stay within the Terms of Service). Just for testing purposes, “Alone again or” by Love in a small audio-only embed (unless you’re on mobile, that is);