I keep getting them as an RE. Can you actually DO anything with them?

In the Lower East Side of Centropolis there is a Coin Machine you can use, but it's a big gamble.

I just got one through a random event. Maybe I will try it. I've never used it before...

EDIT: Copper Special Coin You have 1 coin!

JellyFilled has gained 1 defence point!

I personally gamble on them each time I get one.

I just remembered I have some in my inventory that I can use. Time to gamble!

Good luck! Let me know how you do. I don't run into them often.

Red Special Coin You have 1 coin! Oh, look! The coin popped back out! You receive 3,387 sP!

Slots Coin You have 1 coin! You receive 5,000 sP!

You can actually use the slots coins? I had no idea. Thanks!

Yep, you can! Sure thing.

You see a shiny coin on the ground and decide to pick it up!

Found one today! I guess I have more in my vault, maybe I'll gamble them as well since everyone else on this thread does.