Get future champions 40%ish off.

The mystery champion shard does not expire (Confirmed by Riot), and automatically unlocks a champion you don't own randomly. If you own every champ save these for future releases and get them 40% off of the introductory price.

I keep seeing a lot of people saying the new system "F'd" up veteran players who already own everything... but you just got a massive 100k+ refund to pre-purchase the next year or twos release champions at a massive discount.