Question for Riot about Hextech Crafting and owning all Champions

I know Riot have said that they'll announce more in the future. But having opened 2 of my 4 chests so far this month and both of them giving me champ shards, I'm curious: Should I hold on to my chests? Will whatever system you implement allow us to do something with the shards, or will it make it so we don't get shards? Because if the second, I don't want to waste chests.