Scammers wanting to buy used Phantom wallets?

I got a message recently on Telegram from someone in Nigeria, saying that they buy Phantom wallets with trading history. I guess it's either a scam where I'm the target, or they'd use it to scam others, but I just don't understand how it works.

Let's say I have a wallet I've used for a few swaps. I move whatever's left in it to another wallet, give them the seed phrase, and then walk away. I'm not saying I want to facilitate scammers, but just trying to understand the risk. Maybe they don't want the seed but they want my log in in some other way, I guess? I didn't ask that much.