Music function returning *unspecified*

Are there any potential drawbacks to allowing music functions to return 
*unspecified* and having the infrastructure map it to (make-music 'Music)?

The main advantage is that something like

     (if condition
         (begin
          ...
          ...)
         (make-music 'Music))

could instead be written

     (when condition
       ...
       ...)

I believe that this can be done; I'm asking whether there is any reason 
that it shouldn't be done.

Thanks,
-- 
Dan