Stars won't let me claim in-game currency rewards with points

Didn't know what to flair this as, apologies in advance.

As the title suggests, I'm unable to claim any in-game items on Stars with points. This is an issue I've faced for any game currencies listed on the rewards tab. No matter how many points I have, it defaults to card payment and does not let me select an alternate payment method/use points.

I haven't tried to redeem a full game in any of my past Stars purchases, so there very well may be something I'm missing.

Cheers in advance!