Would it make sense to buy the ETF with no staking income?
That's a good question. It makes sense for people who have no idea about crypto and don't want to learn about it. Just use fiat as a proxy for crypto.
I do think we could see selling pressure from Greyscale once again though.
I don't know what are the details of the Grayscale application for the spot Ethereum ETF, but I suppose a migration of funds to other ETFs is possible here as well.