How do I use the points accrued on my REI MasterCard? They don't show up in my REI Membership account.

You get it all with the yearly dividend

Yearly dividend also depends on how much you spend there will determine what you get back.

March they send out a giftcard with a yearly dividend.

You will automatically receive a gift card in the mail once a year.

I believe they get sent out with (added to) the yearly dividend, around March