TILs (Today I Learned) are useless, have terrible signal-to-noise ratio, create FOMO.

True, but they are not meant to be the best raw material ever made. They are made to add some randomness in your feeds (or way your consume news or content). They are personal. They don't share or are structure as a lesson. Most of the TILs I read are on Mastodon, toots shared on the fly because someone learned something. The tag Today I Learned is missing, but it remains a TIL nonetheless.

TILs are a way to discover things. Why on earth do you need some random facts to spark your interest in something?

Good point.

There are other advantages to the TILs. They can be read on the fly, in public transportations. They don't need focus or immersion as a fiction book needs.

I think in between: a majority of TILs is undesirable, a few can be useful. A balance is healthy. It is sometimes convenient to put your concentration aside, and distract yourself while reading something short.