It is another shop that is still about 2 months away. You can sell all Eidos of R rarity (not the Enhance Material ones) and higher for points. Gacha ones will give more points than event ones. But yes, you can trade in the SSRs as well. If you're low on inventory space just increase it a little. I have all inventories at max upgrades. The trick to it is that you don't have to do it all at once. Personally, when they did these login bonuses that would give us 1500 jewels, I would use about 500 of them towards inventory upgrades. I was still able to pull Gacha and increased my inventory at the same time. And now that we get even more jewels as rewards in events, it is so much easier to do.