WhatsApp Business limits the number of devices that can be connected to 5. This is made up of 1 physical device that has the app installed and then 4 other browsers that are linked by scanning the QR code. For any SMB or Enterprise, this device limit and provisioning process is going to be a major stumbling block.
Imagine the example of an organization with a distributed workforce, which is not that uncommon these days. To get WhatsApp Business set up on 4 other agents' browsers, they would likely have to send a picture of the QR code to the admin with the physical device so that they can authenticate the browser.
3CX API integration
The difference couldn't be greater. By integrating 3CX using the WhatsApp Business API, you can allow an UNLIMITED number of agents access to replying to messages. Having a distributed workforce is not an issue. When a new user is set up with a 3CX account, they receive a welcome email to log into the 3CX Web Client. That means that no matter where they are in the world or what time zone they work, there are zero barriers to getting set up.