Your are likely looking at something similar to the laptop image to the right.
Most people think that Type C devices all run faster that the older rectangular Type A connected devices, but that is not necessarily the case. Type C devices can run at speeds ranging from the old slow USB 2.0 .5Mbs to Thunderbolt speeds of 40Gbs as shown in the graphic below:
Nearly all USB Type C devices run at USB 3.1 speeds of 10Gb per second or faster but that is not a requirement. Further, there are three different generations of Thunderbolt available today, each version runs twice a fast as the previous version.
This means that when you are buying USB C devices that you check the speed. In the world of 2018, I would not buy anything that needed fast connections (i.e. video, external disk…) that was below Thunderbolt 2; otherwise I would just stick with good ‘ol USB 3.1… but that is just me, you may feel differently.