This is usually the time people use to have social multigenerationnal social interactions. Outside of weekends parents have stuff to do all day long, kids have to do their homework, then like to immerse in playing. Sometimes kids and parents spend sometime on a specific game, cards and board games are nice for that, but time is usually against them midweek. Meals and Dinner are those time when family member reconnect and chat. There is no reason to be bored unless your family is totally dysfunctionnal.
I would say even as a single adult, meal can be a perfect time to have that disconnected moment and just think for a little while. Maybe you should try it as an exercise if you don't have those moments in other times of the day.
It is what kids will do.
And I myself have seen this behaviour, presently for kids upto the age of 10 years old (born around 2010), but the behaviour of newer kids born 3-4 years back is quite weird/concerning to me.
Despite not having anything like that as a child I now, at 43 I eat all my meals in front of a computer while gaming or watching something.