When you chat with someone on WhatsApp you are able to see the other person typing while you still wait for the message. Now WhatsApp will also be able to observe as you tap your fingers on keyboards.
The purpose of this monitoring is to differentiate between one-on-one human interaction and automated software and bots. There are firms which use automated software and bots to send hundreds of messages at a time in order to tap consumers.
When you make an account on WhatsApp, the mobile number, IP address, and the carrier information is sent to the servers of WhatsApp. The machine learning skills will figure out if it is a normal or bulk registration. So than the feedback will decide whether the account should be deactivated instantly or will be asked for more details.