I don’t understand why they need a laptop at all.
At DC's private school, parents are required to purchase a school specified touch screen laptop. Children carry them around to their classes so they're locked down and can't be used for most non-school related activities. No social media, no gaming, no streaming, only approved websites.
Teachers set assignments with due dates through the system. Yes, of course, children could keep track of assignments in a paper diary, but it's very useful for them to be able to pull up what homework is known to be due in each of the next few days. Students also upload their work, where appropriate, or just click to indicate that they've completed an assignment and will bring the paper to class.
Teachers put their presentation slides and class notes on the system. Yes, of course, children could copy these down during the lecture, but I'd rather DC was thinking about what was being presented rather than frantically transcribing a board. And having the materials (sort of) organized on a file system helps in case a student is absent on a day, eliminates the possibility that a child loses their notes, and makes it easier when it comes time to revise.
Students do some of their work during class time on the laptops. They may start an essays in English, or they may do some math worksheets, where a touch screen is quite useful, or they may put together a poster for History, etc. Here I have a criticism which is that, while the students compose most of their papers during the term on word processors, during exams they're back to pen and paper. However, my criticism is about the requirement to use pen and paper to compose essays in exams, both at the school and at GCSE or A Level. You may as well give points again for calligraphic penmanship, it's so unreflective of what they will face once they leave school!
And, of course, the children use the laptops for computer science. Yes, of course the children could use shared devices in a computer lab. But it's good that they can easily finish at home the programs they start in class.
None of these things are strictly necessary. After all, very few, if any, of the parents amongst us had them in our own educations. I mean, does anyone need Google Maps, when A-to-Z was available in six different sizes to fit in different types of pockets? But technology can have benefits. At DC's school, AFAIK, nearly all the actual teaching is still done in the traditional manner. The computers mostly reduce the burden of organization and increase the efficiency of the children's study time.