This argument feels ... not quite like a strawman, but more pedantic than I think it needs to be. I don't think anyone really argues that everything should be plain text, even if that's an easy shorthand. The real argument is "use the simplest, most open format possible." Nobody is suggesting you go through all of your photos, transcribe your emotional reaction to each picture, and then delete the image. But, if you…
OTOH there are many photos I have, taken a decade or two ago, where I wish I'd written down my thoughts and reactions at the time, rather than just taken the picture. A picture may be worth a thousand words, but just having lots of pictures and no contemporaneous words, leaves more of a gap the longer ago it was.