> It's acceptable to just pick up your phone now to look up something or check your messages during a conversation in a lull.
I certainly wouldn't find that to be acceptable at all, and if someone I was with did that, I would ask them politely if they had something more important they needed to be doing, and if they wanted to postpone our catch up until later when they weren't as busy.
Arbitrarily scrolling in mid-conversation is rude, but somebody picking up their phone to look something up or read a text message now happens without a big fuss, whereas before, I think people were more likely to apologize for the action. It's acceptable to just pick up your phone now to look up something or check your messages during a conversation in a lull.
On the other hand, I see couples seated together in restaurants just scrolling their phones privately at the same table, so generally it seems like it's more "okay" to disengage to your technology.