Does using a newco to buy assets protect the seller as much as it protects me?

Not really, and it's worth understanding why the benefit runs mostly one way. A newco used as the buyer mainly protects the buyer — isolating this specific acquisition's risk from the buyer's other assets and businesses. It doesn't do much for the seller, whose protection in an asset sale comes from clearly excluding the liabilities they want to keep, and from being paid properly for what they're selling.

If anything, a newco buyer can create a new concern for the seller rather than protection: a freshly incorporated corporation with no operating history, no established assets, and no track record is a weaker credit than an existing, established buyer. That matters most where any part of the price is deferred or secured by a vendor take-back, since the seller is now relying on a brand-new entity's ability to pay over time, and typically wants a personal guarantee or registered security to make up for that.

If you're the seller being asked to accept a newco as buyer, it's reasonable to ask for a personal guarantee, security over the purchased assets, or other assurance the newco can actually perform. A business lawyer can help negotiate that protection into the purchase agreement.