When you switch to WhatsApp Business API, you will lose some of the features you are used to in the WhatsApp and the WhatsApp business App.
Limitations of WhatsApp Business APIs:
You can't access the previous chats with your customers.
You can't use the number anymore as a WhatsApp or WhatsApp business number.
You need to use template messages to reach out to new customers.
You need to use a template message if you wish to reply to customers after the 24-hours reply window.
You can't join a WhatsApp group with your WhatsApp Business API number.
You can't make WhatsApp Voice or Video calls.
You can't Forward WhatsApp messages
You can't reply to a WhatsApp message as a thread.