This sounds stupid, but I work for a company that produces a few product ranges and sells them in different online settings. The product with branding do far, far better. Speaking also as a consumer, when I see a new product for sale that has no branding, I automatically assume it's being sold by a flash-in-the-pan drop shipper trying to make a buck off a product they did not manufacture, which tells me to avoid it.
Since there are a variety of free tools out there to create a simple logo, I'd say at least put that effort in before considering selling. Branding is part of the process flow.
It's possible the OP was just trying out different storefronts and either doesn't have finalized assets or doesn't want to pull them up to try it out. When publishing or going live I agree with you, but in my experience most sitebuilders/storefronts have a draft / unpublished version - in which case uploading logos/product images/favicons/etc - isn't necessary until going live.
I wasn't going to drop ship anything, I've been trying different store fronts with the idea of selling art prints. I don't have a logo for myself, and also I just wanted to try it out and see what it looked like.
Since there are a variety of free tools out there to create a simple logo, I'd say at least put that effort in before considering selling. Branding is part of the process flow.