Being able to change the responsive breakpoints would allow us to set the desired screen widths when the layout of the website would change to tablet and mobile mode.
This is especially helpful when we have some elements on the page that we need to change to a different layout sooner or later than the predefined values. ie. We have a long navigation menu in the header, but the site won’t change its layout to mobile and the menu items gets stacked till the layout gets changed to the mobile version and menu changes to a hamburger menu. Being able to change the value of the mobile menu breakpoint would solve this problem.