\slashedGrace vs \acciaccatura

[Peekay Ex]

Hello,

I am just wanting a clarification of the difference between the
\slashedGrace and \acciaccatura functions.

Is it just that  \acciaccatura is always written with a slur and a
grace note (\slashedGrace) may or may not be?

I wanted to know the difference (musically and perhaps technically)
the difference between

\slashedGrace c8~ c1

and

\acciaccatura c8 c1

So I could accurately document this (with the existing examples).

The output looks the same. Inferring that \slashedGrace c8~ c1 is
redundant as we have \acciaccatura c8 c1.

Thanks for your time.

-- 
--
James