Is there a reason why font size for code is smaller than for text?

Is there a reason why the font size for code is made smaller than normal text?

For example ,if you write `double`s  in Quickbook the 's' is noticeably large than the 'double'.

Do I understand correctly from boostbook.css snip below that  font size of paragraphs is going to be
10 ?

and the code the smaller 9 point?

Is it just me, or does it not look better using the same font size?

Paul

---
Paul A. Bristow,
Prizet Farmhouse, Kendal LA8 8AB  UK
+44 1539 561830  07714330204
[email protected]


 
boostbook.css

/*=============================================================================
    Copyright (c) 2004 Joel de Guzman
    http://spirit.sourceforge.net/

    Distributed under the Boost Software License, Version 1.0. (See accompany-
    ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/

/*=============================================================================
    Body defaults
=============================================================================*/

    body
    {
        margin: 1em;
        font-family: sans-serif;
    }

/*=============================================================================
    Paragraphs
=============================================================================*/

    p
    {
        text-align: left;
        font-size: 10pt;
        line-height: 1.15;
    }

/*=============================================================================
    Program listings
=============================================================================*/

    /* Code on paragraphs */
    p tt.computeroutput
    {
        font-size: 9pt;
    }


---
Paul A. Bristow,
Prizet Farmhouse, Kendal LA8 8AB  UK
+44 1539 561830  07714330204
[email protected]