I suppose it's a compromise; the lower you go, the more control you have.
I used to work on an app where we used the UI builder at the time (I forgot the name) at first, but my colleague asserted that building the UI in code resulted in a faster app, because (according to him) parsing and rendering the XML output took longer than interpreting the code. I don't know if he was right, but a while later Apple introduced devices with different sizes (iirc the iphone 5 which was a little taller and the ipad) and doing all the layouting became impossible.
Anyway when I rejoined later it was a (I believe) healthy mix of the UI builder tool and custom code for some graphic / coded elements (think a fancy progress indicator). I suspect it'll be the same for SwiftUI.
I used to work on an app where we used the UI builder at the time (I forgot the name) at first, but my colleague asserted that building the UI in code resulted in a faster app, because (according to him) parsing and rendering the XML output took longer than interpreting the code. I don't know if he was right, but a while later Apple introduced devices with different sizes (iirc the iphone 5 which was a little taller and the ipad) and doing all the layouting became impossible.
Anyway when I rejoined later it was a (I believe) healthy mix of the UI builder tool and custom code for some graphic / coded elements (think a fancy progress indicator). I suspect it'll be the same for SwiftUI.