I know this question is beyond basic but for some reason, I'm just not comprehending when I should or would want to use this type of input type in a web form/survey. I've created a number of these now and have never used this input type but wonder what I'm missing out on. To be clear here's an example of the input type:
<input type="hidden" value="us_only" name="site" id="search-site">
whomever responds, please give me some pratical examples of when, where and why I would use this input type.