The answer depends on your needs. Wholesalers and distributors may not need as deep an integration if customers don’t have unique business rules (for example, the merchant offers the same pricing and inventory data to every customer). In these scenarios, a simple, B2C-style platform and architecture is often adequate.
However, manufacturers typically need much deeper ERP integration in their B2B ordering portals. Typically, each customer has unique business rules governing pricing, SKU permissions, inventory/ATP availability, and more, all of which require an ERP integration that’s “always on” and up-to-date. In these scenarios, a B2B portal which includes ERP integration is often a better fit, as it avoids the cost and risk of middleware-based integration architecture.