why use simple_form

1. Required fields are marked with an * prepended to their labels.
2. Simple Form also lets you overwrite the default input type it creates:
3. You can overwrite the default label by passing it to the input method. You can also add a hint or even a placeholder. For boolean inputs, you can add an inline label as well.
4. It is also possible to pass any html attribute straight to the input, by using the :input_html option.

[reference]

https://github.com/plataformatec/simple_form