Facebook's $19 billion acquisition of WhatsApp was still a hot topic on day three of Mobile World Congress in Barcelona, with Amdocs' director of market insight and strategy describing it as a way for the social networking giant to reconnect with some of its users.

"A lot of youngsters only use WhatsApp for all their interaction with friends," Michal Harris explained to Total Telecom.

By acquiring WhatsApp, "Facebook is gaining back a customer segment that they were beginning to lose," she said.

The deal also represents a tacit admission by the world's largest social network that its own messaging platform, Facebook Messenger, is not up to scratch.

Facebook CEO Mark Zuckerberg has defended the $19 billion price tag on the grounds that WhatsApp is well on its way to reaching a billion users, making it a highly-valued asset.

"Think of the power of saying you serve 1 billion customers," Harris said.

Indeed, with WhatsApp revealing earlier in the week that it plans to add voice calling to its proposition, it has the potential to become a bigger player in the voice market than Skype, which has around 300 million users compared to WhatsApp's 450 million, and certainly bigger than most operators.

When WhatsApp is considered in those terms, $19 billion does not look quite so expensive, Harris noted.

"Somebody worked out that the [$130 billion] Verizon/Vodafone deal came to around $2,000 per customer, compared to around $40 per customer for WhatsApp," she said.