Wallets don't have earning power the coins do :)

However, whether your DEC is sitting in Splinterlands or on Hive-Engine, or on Tribaldex Liquidity pool they will get you the same airdrop rewards. SPS won't get you anything on hive-engine. Will get you interest if staked in Splinterlands. Will count if added to liquidity pool along with DEC on Tribaldex.