Would it be better to just connect devices directly into StellarWiFi Ethernet port on a pod versus over WiFi?

You will enjoy slightly faster speeds on your device when you hardwire them to a pod by Ethernet cable. 

Connecting a device to a pod by Ethernet will not impact your StellarWiFi performance negatively.

Please note that you may need to power cycle the pod you have connected to your device for StellarWiFi to properly recognize and add it to your network.