I have experience selling my old ETH addresses and ended up being scammed. I'm not sure if some of you would consider this a scam, as I agreed on the price for selling my ETH addresses and received the payment. They just took advantage of me for not knowing that the address I owned had an unclaimed Airdrop. I just found out that there's an unclaimed Airdrop after transaction and checking the transactions linked to my Ethereum address.
I don't think that it can be called as scam. As you said, you both agreed price, you got money, he got ETH addresses. He wasn't obligated to tell you why he needs these addresses and haven't done anything illegal. He simply benefited from that you wasn't aware about airdrop.
OP saying that he need it not for airdrops, I'm wondering what other reasons can be.