bug#21563: 24.5; discourage load-hook variables

[Roland Winkler]

On Wed Jan 15 2020 Stefan Kangas wrote:
> Drew Adams <drew.adams@oracle.com> writes:
> > Setting or changing the explicit hook value has
> > no effect if the library was already loaded, whereas
> > `(with-)eval-after-load' has an immediate effect in 
> > that case.  (Sure, the latter could test in its body
> > whether it's loaded and act conditionally...)
> 
> Good point.  So it seems like load-hooks and eval-after-load are
> slightly different and could both be useful.

What is the benefit of being able to put something into a load-hook
that will be ignored because the feature was already loaded?
Is there a real-world example that can illustrate how this is
useful?