Define "simple".
It can generate very complex layouts, without inputing a single line of code.
It's more capable than any other layouting system.
As the VFL docs say, "The notation prefers good visualization over completeness of expressibility." For example, it's impossible to create an item with equal height and width in VFL. It's definitely not more capable than other layout systems. It's strictly less capable than auto-layout, for one.
I don’t agree with grandparent’s characterization of autolayout, though.