the end of keys?

http://zeenews.india.com/news/net-news/soon-smartphone-app-that-can-open-doors_820767.html

"NFC interface and door locks only operate within a narrow bandwidth and have limited computing power. Consequently, scientists at the SIT have equipped ShareKey with particularly resource-efficient communication protocols. Further, electronic keys are reliably protected on the smartphone from malware and unauthorized access.

This is achieved by leveraging advanced technologies which keep sensitive data on the smartphone separate from other data and apps lik Fraunhofer’s BizzTrust.

Communication between the mobile phone and a central server is protected by established security protocols.

'And even if this communication is hacked into, it’s impossible for unauthorized people to gain access to the digital key. This is because opening the door requires information contained both in the encrypted token sent to the user and in the app installed on their smartphone,' Dmitrienko said."

I don't see any downside except if your smart phone battery goes dead.