FIORI Security gotcha : Protocol cannot be switched to HTTPS: HTTPS is not configured / active

Working on a FIORI development recently, I got flummoxed by the following error, observed when running the Gateway transaction /UI2/FLP to access the launchpad : 

This was aiming for URL :

http://<gateway box>:8000/sap/bc/ui2/flp?sap-client=001&sap-language=EN

However, other users were aiming for the following, which worked:

http://<gateway box>:8000/sap/bc/ui5_ui5/ui2/ushell/shells/abap/Fiorilaunchpad.html?sap-client=001&sap-language=EN#Shell-home

Without much explanation... but this is your workaround!