The `:` is not visual noise, it indicates that it is a keyword. Without it, you're indicating that you're writing a symbol. Symbols are evaluated, so keywords is a better choice given that they always are what they say they are, whereas you could define `div` to mean `<p>`, point to a function, or any number of other things.

You could write a macro to use symbol names literally, so that `div` always means `<div>`, but then you'd have a macro where none was needed, and you'd have no obvious way of using symbols in a non-literal/evaluated way.

Fulcro[1] lies little closer to what you're after. The above would be:

  (div 
    (p "I am a component!")
    (p :.someclass
       "I have " (strong "bold")
       (span {:style {:color "red"}} "and red") "text."))

This is since Fulcro defines the element tags as functions, which are called in order, rather than as a data structure that's interpreted (a la Hiccup).

The immediate and obvious benefit of Hiccup over the function hierarchy is that Hiccup can be trivially (and safely) seralized/deserialized.

1: https://github.com/fulcrologic/fulcro