Yes, absolutely! Actually using the RJ45 internet cable will probably provide a more stable and secure connection during video calls then WiFi. Actually video-calls use a compressed video format to drastically save bandwidth and amount of data to be transferred. These video calls only use a fraction of the Gigabit bandwidth.
1 Gigabit is 1000 Megabit, which is 125MB. So 1Gbps means a max data transfer speed of 125MB/s. For reference photo's usually are around 2-10MB.
To fully enjoy the Gigabit speeds we recommend to use Gigabit router/network devices in combination with CAT5e or CAT6 cables. Please note that if your network device (router/switch/hub) is only 100M the Multiport hub Ethernet port will only function on 100M speeds.
This is perfectly normal, a lot depends not only on the 'connection' but also if you are reading or writing to a hard drive or SSD, to a USB stick (or from a USB stick) or to a network attached storage device. Often reading from such devices goes much quicker then writing to them.
Actually our hubs feature 'up to 4K@60Hz' HDMI video output. For that to work properly on our Multiport hub we need to have our hub in default of USB2.0 speeds (theoretic max of 480Mbps). Having said that, our hubs have a switching protocol which steps up to USB3.1 Gen1 when a USB3.0/3.1 device (i.e. memory stick) is inserted. With the hub stepping up to USB3.1 Gen1 also the ethernet port will achieve the max 1Gbps speeds and the HDMI output will step down to 4K@30Hz to prioritize bandwidth for USB3.1 Gen1 usage.