Key Points
Customer
We are stuck with technology when what we really want is just stuff that works.
Fully responsive across any device
Small footprint is cached to yield fast time to first paint
Reduced number of HTML tags yields faster render
Selectable font size and selectable light / dark mode for better accessibility
Business
Good companies manage Engineering. Great companies manage Product.
Future proofed - HTML5 and CSS3 Standards compliant
Stay out of legal quagmire - meets WebAim accessibility requirements
Lower cost - no javascript means less code
Simplify maintenance - expected to be THE source of truth
Technology
It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change
No breakpoints - uses design widths
Simplified customization with CSS variables
No dependencies and no bundler required
Supports split complementary colour scheme