Most schools do t post out results now.
Some put them on an internal portal for students to see, or will email to the students school email address. Sometimes they have had to give permission for them to be sent in this way. Some might have asked for a stamped addressed envelope in advance for them to be posted.
Especially for anyone going elsewhere than their school for 6th Form, you really do t want to be waiting for a letter delivery. They shouldn’t post until results day and then it could be Saturday or Monday before they arrive. If they haven’t got the grades they need, you need to be on hand to take action immediately.
I’m always surprised how many people are on holiday on results day. Being at school allows students to find out grade boundaries and see if they just missed a grade or just scraped it, and put in for re-marks if sensible, plus access support and advice from subject teachers. It often allows them to firm up A Level choices and if discussion about change is needed, to have it there are then in person. These things are possible remotely, but especially if not done on the day can be more tricky. Teachers will be in and working on results day, but many go away for more holiday or are much less available from the day after as they want to enjoy the last week of their holiday. Especially if there needs to be a bit of switching of subject choices in light of results, or putting a case to be allowed to do do something where the required grades haven’t quite been met, doing it all in person on the day can be really productive, plus it means it can be done and dusted. No-one wants to spend the following weekend worrying about what’s happening next and not being able to do anything about it. of course, if a student is moving to another school or college, they might not be seeing anyone about options until the following week anyway, so perhaps being there isn’t so important.
I’d think any student would want to know how clear they were into the the grade they got and how far off the grade above - that info isn’t on results slips, so discussion with teachers can be really useful. I think loads of students never get this info and remain oblivious to the fact they missed the higher grade by 1 mark, and that their teacher might have been a bit disappointed in the result and wondered if a re-mark might be worth considering.