If hackers can steal the private key to your airdrop wallet, they can definitely get the private key to your trading wallet. It seems like a good idea in theory to separate them, but in practice, I don't think it would make much of a difference.
It would because if you get hacked, only one account gets hacked. And you would not use your trading address in any airdrops or shady websites that would try to scam or steal your address. But the strict rule should to never give away your private keys. Always keep it safe and your funds are safe.