The wholesale model assumes that the platform in question (Amazon, Zalando, etc.) buys part of the products-at a wholesale price-directly from the brands. The brand is not in charge of the online sales aspects (product publishing, customer service, etc.) but has no power in defining content or prices, resulting in a thinning of margins. Moreover, it is the marketplace that defines what to buy (often only a small selection of products).
If the brand sells on marketplaces as a seller, it gets higher margins and controls all aspects of online sales, provided it has the resources and in-house expertise to do so. In fact, it needs a team dedicated to creating catalogs, logistics, returns and customer service, etc.
The third option, namely relying on a partner (who sells in seller mode), means benefiting from all the advantages of the seller model without worrying about the operational aspects of selling online. It is the partner who takes care of everything: logistics, shipping, returns, marketing, content, etc.