The purpose of the site "Can I use" provides up-to-date browser support tables for support of front-end web technologies on desktop and mobile web browsers.
Ways I can use the data presented are if I wanted to
Float: The float CSS property places an element on the left or right side of its container,
allowig text and inline elements to wrap around it. The element is removed from the normal flow of the page, though still remaining a part of the flow
(in contrast to absolute positioning).
Grid: The Grid CSS is a method of using a grid concept to lay out content, providing a mechanism for the authors to divide
available space for layout into columns and rows using a set of predictable sizing behaviors.
In summary, the "Can I Use" website is a helpful resouce that allows you to see what features are compatible and supported with certain browsers.