I think the biggest risk of L2 solutions is centralization. Look for example at Immutable's (Makers of the Gods Unchained TCG) IMX. IMX currently holds all the NFTs for GU, those are cards for playing the game. It allows users to trade/sell card in a fast way without gas fees. Here is the issue, all players with cards are functionally locked into using IMX both for gameplay reasons and the gas required to leave IMX and remint cards on L1 would be outrageous.