While a USB-C card reader won't necessarily give you all the options that the best USB-C hubs for Mac can, they are typically less expensive. The best USB-C card readers for Mac will let you connect your SD cards, microSD, and in some cases, even Compact Flash card to your Mac, so you can transfer files and photos with ease. All the Mac laptops (both the MacBook Air and MacBook Pro) only have Thunderbolt 3 (aka USB-C) ports, and that has left a lot of people scrambling for dongles, including card readers.
USB-C is becoming the new standard connector and Apple is jumping on board in a big way.