Doing a DACUS, aerial, jab combo, another grab, or even a forward b after a down throw >>> Shine after a down throw. It's only 5% lol.
Going off what TheX0913 said, it's more of a "get away from me" move because of how fast it comes out and it's decent rage. If you want to combo with it, you're playing the wrong game.
The only times I finding myself using shine is catching people in short hops, edgeguarding (not what you might think), reflecting..., and doing it after a Jab combo or SHDL (to avoid being punished).
I like the tripping effect to the shine since it gives you a chance to punish rolls with a smash.