With regards to gold coins, I've developed the habit of waiting till I have a certain amount of coins, like 500 and then buying something with that. Right now, I'm aiming for 1,000 coins. Once I get that, I'll buy something that's $10 or get a $10 discount one something more expensive. I'm going to make an exception this month, however. Since, it's my birthday month, Nintendo sent me a 30% voucher I can use on a couple of games, I'm eyeing Metroid Samus Returns and Mario and Luigi Superstar Saga. But then, there's an offer where if I use up 90 gold coins, I can get a 30% discount on Metroid Samus Returns. So, I'm going to wait till next Thursday to see if by any chance either of these games goes on sale for 30%. It has already happened once before with Samus Returns but I was not wise enough to jump on the offer. So, in the off chance that happens, I'll nab both games for 30% and keep the 90 coins. If not, I'll spend the 90 coins and get $13 off.
I use my coins on any games which can be bought outright from the MyNintendo site, seems like the best value for them. I've also redeemed for a couple of game discounts on stuff I was curious about, like Tank Troopers.
@Anand Yeah, that statue was cool! I have the original Club Nintendo statue that features a lot of Mario characters. It seems that the new Switch Online Service will also provide a way to get exclusive swag like that, the first example being the wireless NES Switch controllers.
@Anand I don't think I had enough coins for that Luigi statue either, if I remember rightly it was the highest coin value of any prize ever offered. I didn't get the Kirby medal either, might have been for the same reason.
I was planning to save them up for some pointless merch or possibly spend a few here and there on various digital Switch games, but I ended up spending all of them to get a hefty discount on Cities Skylines.
As for the platinum points they are mostly just sitting around until they expire. I sometimes use them to download wallpapers for my laptop and phone, and I've used some to get 3DS themes, but right now there's just nothing there for me.
I do remember my nephews ripping open my carefully concealed Animal Crossing card deck to play freaking Speed, or something. Instead of utilizing the well-stocked card/chips/dice bag already in the living room. GAAHHH!
My younger nephew was always trying to get into my giant Club Nintendo Question Block box, too. I was all "Why are you so obsessed with my forbidden box of mystery?!"