If you purchased a Hotspot V2 with native PoE, you will be able to plug in a PoE-enabled Ethernet cable directly into the hotspot and you will not need a power cable anymore.
This of course still means that the device on "the other end" of the LAN cable needs to provide power through PoE. Just plugging in the LAN cable in a standard internet router and plugging the other end into the Hotspot does NOT mean that you will receive power through PoE.
Either you have PoE-enabled switches, or use injectors to provide power.