The original MCR program ended in June. There is no way to accumulate points to redeem for gift cards or merchandise ever again (unless Coke decides to revive/reinvent the program).
https://us.coca-cola.com/offers/ is the new program. Codes now only have a single value, regardless of source (cap or 12-pk flap or whatever), and can be entered for contests and occasional items and coupons. For example, there is currently an offer to get a large popcorn at AMC theaters by entering ten codes.
So, don’t just throw out unredeemed codes just yet, but no, they don’t have the same value they used to have.