Secure encrypted login data usage

I have a query about data usage for secure encrypted login. I don't know what this is. Google tells me it is what allows me secure access to websites and apps requiring additional security so I am guessing this would include email, banking apps and WhatsApp, for example. But why is the data usage showing up separately from those as an additional billing item?

I am asking the question here because the customer service agents at my local Vodacom store are without exception superior, rude, and unhelpful, and often downright wrong. They treat customers like little children with stupid questions that are below their dignity to answer properly.