Header and footer blocks are usually used to display navigation, store switcher and currency, a search box or top prior links relating to desired pages. The Magento default headers and footers are somehow too basic.
They keep the same through all the pages of the site. Thus, they may reduce the joy of visitors while surfing the site that leads to the risk of leaving your site without placing an order. To prevent that risk, make your headers and footers more attractive! And Header & Footer Builder in Magento 2 is the tool you need.