You will be able to use WhatsApp on several phones simultaneously
One of the limitations of the messaging application was the authentication on a single device. But this will disappear in the near future and you will be able to use the WhatsApp account on several phones.
This new update that brings WhatsApp account synchronization across multiple devices is under test. We don’t know exactly when it will come, but most likely this year if things go well.
As to how useful this function is, I don’t think it’s worth explaining. I am sure you have also encountered this limitation. For example, when I test multiple phones simultaneously it would help me to have WhatsApp on all.
