The difference is the Shorts format tips the scales. Somebody might want one and not the other.
When the written word took over with the printing press, the same concern was levied. The amount of attention required to listen and memorize a story/poem is a lot more than just reading it.
The change with smart phones is just one of access/time spent on these things. There are people who are spending ~5 hours/day watching this content. There is a big difference between someone listening to 5 hours of a single poem, to reading 5 hours of a single book, to reading 5 hours of blog posts, to watching 5 hours of a youtube video, to watching 5 hours of random videos, to 5 hours of <10s videos.
I only get what the creator wants to communicate, which is almost always misleading or missing details.
It’s an awful medium for communicating and I feel like I’m being misled every time I see short form content, which is rarely since I avoid it at all costs. At least with a longer video there is more substance to evaluate to tell whether the creator is worth trusting.
For some others, shorts are too much of a temptation. You can find a lot of comments even on HN from people admitting that short-form video content on any platform (YouTube, Instagram, TikTok) can pull them into a time warp where they've wasted more time than they wanted to spend on videos. I suppose there are some people who can manage long-form YouTube use but struggle with shorts, but I suspect a better solution for people with self-control challenges is to disable recommendations completely (which will also make YT shorts disappear)