Basically the title. If it feels like the new method in iOS 17 of hitting the plus symbol, then scrolling up and then selecting photos in iMessage takes too long you can just long hold the plus symbol and it’ll short cut to pics.
Edit: Also you can drag and rearrange apps in the + menu as well.
The lack of discoverability is the biggest problem with long press interactions. If something looks like a button a user knows they can press it, but there’s no visual indication something can be long pressed.