hope someone could clear up?

perlootut, Modern Perl

What is the reason for the first argument that is passed to the routine in a class being the class name?

Implementation detail

Is this useful in certain ways?

Without this there is no OO

Secondly,

See above :)

Is there good reasons why this is the case,

See above, thats the way it is, the way it works

or am I doing something really silly!?

:) Somehow you managed to discover a lot without stumbling upon perlootut, http://modernperlbooks.com/books/modern_perl/index.html, or equivalent