Most native frameworks provide tools to position elements, although at the end of the day they are just positioning things on an x,y,z axis.
Using CSS and JS you can do the same thing, respond to events and re-position your elements.
The problem is, people get preachy about how you shouldn't use JS for this, because websites should be progressive and degrade gracefully. Native code doesn't have this problem as much as it's not only accepted, but viewed as cool when you only support the latest OS version (iOS7).
My main problem is not only layout, but the whole design stack.
I do like UI programming, but like many of us I am a bit lacking in the design area.
Native toolkits allow me to ramp up pretty quickly UI thanks to components and layout managers. When something is missing I can drop down to pure graphics programming.
With web designs, it doesn't matter how much I try, without the help of a designer guy on the team, I always end up hacking around until something kind of works, repeating it ad nauseum for all required platforms.
