SPN truly hides your traffic among all users.
Because we take the raw data we can make sure that every packet in the SPN looks the same, thereby avoiding traffic analysis.
An observer of the network can’t distinguish traffic patterns.
Every user looks the same in the network.
To further this traffic gets mixed multiple times.
It is like an Amazon delivery (if they would only use one size boxes), all packages look the same from the outside, and like with the Amazon packages we do put some air in the packages to make them all the same size as well.
Each Virtual Private Network (VPN) is piping connections through to another location.
Because they take the connection, the data sent has already been packeted for the transfer.
What the VPN does is wrap the packet into a layer of encryption, but like the picture of the toy wrapped in paper, you can see a lot form the outside and follow the package around.
IVPN did actually a good explanation of this as well: Can ISPs NetFlow data be used to track traffic going through VPNs?