As an infoproduct seller myself, I disagree, but as you can imagine I'm probably a little bias.
The question should be, can BHW members make informed decisions about the infoproducts they purchase? and do these products solve an actual problem? I think, most of the time, yes.
The difference between BHW and WF is that here you have mods that genuinely care about the users and are looking after their best interest, which is why they wouldn't let bad products go on sale.
People will buy infoproducts whether they are allowed on BHW or not, and I think having inforproducts allowed on BHW will help protect them from "malicious" marketplaces that will take advantage of the uninformed consumer such as that of WF.
Regarding giving less of an incentive to share, my theory is those who care about the community will share, and those who don't, will not. I myself deeply care about the BHW community which is why I'm currently working on multiple threads that I hope can help others, and I believe anyone who cares will do the same, plus as long as we have a competitive marketplace, sellers will always be motivated to share free knowledge to gain the trust of members, the more competition the more free information.
Lastly, a good infoproduct will always help protect the consumer from bad service sellers. For example, an eBook that will teach you how to build your own links will always be more valuable to a community than service seller that sells/creates these links as a service.
I do agree that maybe having higher standards for infoproducts would be better for everyone, but creating and enforcing such standards correctly and in a fair way would likely be very difficult for the mods to do, so perhaps it's just better to let the marketplace filter out bad products by itself.
My $0.02