"daily encrypted traffic" still says "zero KB of 200MB"

I'm new to using my free VPN with Bitdefender mobile security on my iPhone 12 Pro Max.

I thought that the VPN, once "connected" would channel all WiFi data traffic through it.

Before being confident to use the VPN on public networks, I am trying it at home on my home WiFi.

I connected the VPN, the 'Daily encrypted traffic' said 'zero KB of 200MB';

then I emailed a 12MB photo, and downloaded a couple of stock photos from a free photo site about 5-10MB each.

The 'Daily encrypted traffic' still said 'zero KB of 200MB'

I would have thought that the encrypted traffic log should have increased according to the size of the images I had just downloaded and uploaded?

Have I misunderstood how this should work?