This is indeed an easy way to fix text rendering in your inputs and textareas. However, you'll also need to do the same for elements that render the submitted text. And once you encounter bidirectional text (e.g. an English product name within an Arabic paragraph), that opens up another whole can of worms...

Note also that there's currently a regression in Chrome that affects how RTL text is rendered in inputs with dir='auto'. They just shipped a fix though so it should be included in the next release.