I think that a snack is a small amount of something, not intended to be a full meal. But if the food you’ve packed up is intended to be one of the main meals of the day, then it is a packed meal, not a snack - even if it contains some snack type items. So, for example, a packet of crisps on its own, eaten between meals, is clearly a snack, but if you have the crisps as part of a packed lunch (eg. sandwich, with crisps and fruit), then they are a side dish of the main meal, not a snack.
So, in my mind, if you pack up a number of different snacks, intending to feed all/most of them to your child at lunch time, then it’s a packed lunch, not a few snacks.
Clearly, if you have a child with allergies, or one who has sensory issues with food, or even one who is very picky about food, it makes sense to make sure you have food your child can eat with you. And having a snack to give your child whilst you wait for the food to arrive may be sensible too. But I do think most children should be able to eat something from most cafe menus, and once your child can eat from the cafe menu, you shouldn’t be bringing a full packed lunch for them.
As I said earlier in the thread - we managed to eat out with three small children without ever taking our own food or snacks with us, once they were weaned off puréed food. Maybe we were just lucky, but I do think it helped that the boys knew we didn’t have any snacks with us, so there was no point asking, while we waited for the food to arrive. Plus we tried to avoid places where there would be a long wait for food, and went to places where we were confident that either the food would arrive quickly, or where they’d bring something like bread or prawn crackers as soon as you sat down.