I find some of the strict limits people are sharing here very surprising, as in real life I have never known anyone limit their kids' screen time in anything like this way.
I am assuming therefore that these are no or low-screen houses, with no TV, adults only using their phones for work, essential communication or fact finding or in an emergency situation. Otherwise, the level of hypocrisy would be extraordinary.
Given that I myself used screens like the majority of adults - I enjoy watching all kinds of things on TV (both educational, cultural and informative; I used my phone for pleasurable socialising and entertainment, etc etc) it seemed sane to give my child the opportunity to enjoy the same leisure activities (in child appropriate forms). We enjoyed some great experiences together watching films, wonderful documentaries, musicals etc on TV when she was little. There were certain apps we let her have on her iPad I can still remember now, that both seemed educational and gave her great pleasure. To me, technology can provide access to social many beautiful and moving, mind-expanding or just FUN experiences, and we can all learn so much through it.
There was no need for timers as, as is normal for parents if young kids, her dad and I provided her with a wide range of leisure options (park, boardgames, imaginative play, active play, reading, crafts, jigsaws, etc etc etc etc - all the numerous stuff people do with kids) , so there was never need to? Other activities and the needs to eat and sleep obviously provided natural limits.
Not to brag (seriously, I am just making a point) my daughter is currently a teenager and top of all Humanities subjects at least (also strong in the others) in the very selective private school she attends. She's also a lovely person with a wide social circle and a broad balance of interests.
Sadly, a lot of children denied access to TVs etc are shunned by other students - I have taught for decades in various contexts and seen this repeatedly, pretty much without exception, to the handful of students one finds who are in this situation. Understandably, they become unhappy and socially awkward.
I like to think that almost everyone acts in good faith where their children are concerned, hard as their reasoning can be to fathom sometines. There djmww assume parents who make this choice for their children have compelling reasons for the absence of screens in their homes - strong religious convictions or environmental reasons for example - which, to them at least, justify the additional hardships their children undergo.