Its easier to remember a colours Name.
Its harder to remember a colours HEX or RGB codes.
Screen printers and sign writers will be able to look up the codes and get an exact match to keep with your branding.
Modern browsers support 140 named colours, which are listed below.
You can use the colour in your HTML and CSS by Name, Hex Code or RGB Value.
This reference is very useful for developing an initial colour scheme for your websites primary, secondary and tertiary colours.