The difference between HTTP and HTTPS is the security. The (S) in HTTPS stands for secure. HTTPS uses TLS (or SSL) to encrypt HTTP requests and responses.
In most cases, you will want to use HTTPS for the added security. Cases where you would not need or want to use HTTPS would be things like local connections, since local connections never go outside of your network.
If you are connecting to the recorder over OWS, then you are already using HTTPS. However, if you are not using OWS and would like to use HTTPS, follow the instructions below to set your recorder up for HTTPS only connections.
Navigate to the Setup menu.
Navigate to the Network Configuration section.
Check the box option for HTTPS Only. Click Enable and then click save in the bottom right corner.