Good points! Here are some other benefits just to add to your list:

• Extendable styles (works for both styles components and your custom ones) so no more redundant styling code
• Reusable animations
• Can reference other styled components as a CSS selector (ex. triggering a style change of a button based on a hover event of its neighbor)
• automatic vendor prefixing
• Themes and child themes. Perfect for creating and sharing your component library since users can create child themes and easily override styles