In my opinion, Lightweight Portable Security (LPS) is designed for accessing United States Army Combined Arms Center (CAC) and PIV-restricted US government websites with USB smart card reader by US Army.
If you are not an US Army, it is the same risk to use any Linux Live system as LPS. Almost all Linux Live systems are not up-to-date and it is the same as LPS (the latest version is dated on April 16, 2013).
Even the vulnerability is only infected in a session of the live system, you are still in a risk when doing any sensitive activities, such as online banking.