Since Powerline adapters operate over mains wiring rather than a normal UTP cable then they provide a wired connection.
Assuming this relates to security, then you should not have any WiFi Powerline adapters, and you possibly should turn off WiFi in your router.
Security of Powerline versus UTP (Ethernet) cables should come out in favour of Powerline. Powerline systems use encryption, which you can configure yourself, between the adapters, while normal Ethernet is not encrypted. With normal unscreened Ethernet cables, and suitable equipment and access to the cable, without actually touching the cable, it should be possible to pick up sufficient signal from the cable to 'listen in' on what is being transferred. This applies to 10 and 100 Mbps Ethernet. Faster Ethernet splits the data across multiple pairs making it much more difficult to intercept.
When I was working from home, I had an end-to-end VPN that meant there was an extra level of encryption applied even before the data reached the network adapter in my PC, that was removed only by the matching VPN end-point in my employer's server. This applied over both wired and wireless connections.
I hope this helps.