Magento 2.0 already introduces lazy evaluation of JavaScript as a part of the JS bundling feature. This way, we reach the same effect of avoiding parsing and evaluation operations that can be reached by moving JS to the bottom of the page.
The styles portion of Magento 2.0 is not comparable to the size of JavaScript, thus deferred processing of styles by moving them to the bottom page is not expected to bring significant performance improvements. Styles and JavaScript can also be moved to the bottom of the page by layout definition.