Then you are either older, lucky or never introspected.
I assume lucky for a moment.
The problem is less that conversations are more delayed or ad-hoc but more that they can potentially miss out on "group events". And that is where the problem starts. Because they also can't join in on conversations about that event, etc. This means while the rest of the group will frequently have situations where they emotionally bond you get are not included and in turn get subtle unintended socially isolated.
If you are a socially very adapted child you can probably compensate this just fine.
If you have other more important friend groups it probably also doesn't matter too much.
If there is a group of people (not just a small minority) in the same situation as you in the same social circle it also probably is fine.
but if not it really can hurt, and you likely only notice how damaging it was for your social life after the damage is already done and hard to recover even if you now convince your parents to give your more leeway
and that's under the assumption the social group in question is "nice" but you e.g. can't choose the people you go to school with and a not so nice social group can use this to intentionally exclude it or use it as a starting point for bullying which often is only addressed when it has gone out of hand to a point where a parent or teacher stepping in can't fix anything anymore
and sure above's arguments often matter much more for e.g. multiplayer computer games then for "having a phone", through not having a phone also means e.g. not having a camera and not being able to make and share group photos with your social group
instead of denying access to a phone, social media, etc. it's better to control it in a careful and reasonable way. E.g. don't forbid the playing of idk. Fortnight, but explain the problems with it and maybe limit the hours and similar a child can spend, but allow the child to decide when to spend them and allow some degree of saving up hours etc. Similar for social media, etc.
Same applies for going out etc. as far as I can tell it's best for you child to allows it a wide leeway just not unlimited and properly educate them about dangers.
EDIT: deleted the last paragraph it was off topic