When done correctly an author can use the presence of objective info about characters to tell interesting stories. Some tales include an objective arbitrator of the “rules” (often just called The System) which can be used as an interesting plot device.
It could be argued the OG Jumanji counts.

My personal take: it’s what happens when you introduce game mechanics into a setting in a diegetic way. The simplest example is if the characters in the most recent story you read could suddenly perceive that they had stats and attributes like a D&D or video game character.

Have you ever thought to yourself: “I wish there was a science-fantasy LitRPG that spends 16 chapters on character establishment before finally introducing the System?”

If so, you’d be the first. But hey, I’m writing it anyway.

www.royalroad.com/fiction/9824...

So is any work of fiction an isekai by this logic? I ask because I’m into expanding my “your favorite childhood stories were all isekais” argument. 😆

Hi all, I'm Ryn and I write litrpg under my dead name turned penname Jonathan Smidt! For those who don't know, litrpg novels are books with video game mechanics added to them (think like isekai anime and such). If you enjoy video games and DnD, you'll enjoy these!

www.amazon.com/stores/Jonat...

There's a bizarre and ongoing mainstream effort to launder RFK Jr into someone who just wants to get Americans eating nutritious food and exercising again but that is not evidenced anywhere in his public statements or career in public life.

He is a liar and conspiracist.

Electrolytes, Turbolytes, Powerlytes—MORE LYTES THAN YOUR BODY HAS ROOM FOR.
— Me at the 7-11 picking up a Powerade, every time, for 17 years