keyboard macro syntax

[harven]

There seems to be two different syntaxes for keyboard macros, 
depending whether they are named using the commands
name-last-kbd-macro or kmacro-name-last-macro e.g.

(fset 'hello1
   [?\C-s ?h ?e ?l ?l ?o ?\C-m ?, ?  ?w ?o ?r ?l ?d ?! ?\C-u ?\C- ])

(fset 'hello2
   (lambda (&optional arg) "Keyboard macro." (interactive "p") 
(kmacro-exec-ring-item (quote ([19 104 101 108 108 111 13 44 119 111 114 108 
100 33 21 67108896] 0 "%d")) arg)))

Anyone knows why ?

The first one is more readable but I suspect the second one is the preferred 
one 
since it is granted a keybinding (C-x C-k n).