The coins are a "fun" value add thing. You can get small discounts on digital games if you use the gold ones. The silver ones can get you various digital/physical goodies. You're not missing out if you don't use them.
Why make them expire though? Even worse, they expire the coins gradually, stretching it out as long as possible, like radioactive decay. And they send you an email to remind you every time a few coins expire.
This is not fun! This is straightforward psychological manipulation! It’s taking people’s loss aversion [1] and grinding it as hard as possible for as much profit as they can. This is especially bad when you consider that they are a family-oriented company that primarily markets to children.
I don't believe that's true; unused gold coins expire at the end of the same month during which you acquired them, one year later. (I believe silver/platinum coins are similar, but only last six months)
So for example if you acquired 10 gold coins during July 2020 (it doesn't matter when or how many purchases or how spread they are through the month), all ten of those coins would expire simultaneously at the end of July 2021, while any coins you acquired later would remain. It's not a radioactive decay at all; it's a simple expiration date on each individual coin, like you get on coupons or other incentive programs.
The coins expire for the same reason that coupons expire, airline loyalty program miles expire, etc -- they're a liability on the company's balance sheet which potentially could build up infinitely if there wasn't some limit to how long they needed to be tracked and redeemable.
I never got such an email, so I guess you are subscribed to their newsletter? Just unsubscribe if that's the case.
Regarding e-shop: I'd never let my hypothetical children have access to any kind of e-shop where you can purchase without me having to confirm. Parental controls FTW.
The alternative is to uncheck “save payment method for future purchases”.
