(Slightly OT) Forwarding email: inline vs as attachment

[Eric "Shubes"]

I seem to remember reading something some time ago that led me to 
believe that forwarding "as attachment" was preferable (somehow better) 
than forwarding "inline". I may be mistaken.

In the Thunderbird tutorial, I see this:
Unless you have specific reasons not to include an email forward inline, 
you should let emails be forwarded inline, by consideration for the 
recipient: scrolling down is a lot easier than double clicking an email 
attachment.

Can anyone explain why one would want to forward as attachment?

TIA
-- 
-Eric 'shubes'