They don't work with accessories even though they are "MFi" certified (which means they *should* work with accessories). They may work well with headphones (as advertised), but to work with card readers and other accessories, order the CORRECT item from Apple. I didn't even try the headphones because I didn't buy them for that.
Ultimate Compatibility: USB C to HDMI Adapter for MacBook, iPad, Dell, Surface & More
12 Review
4K / 30Hz USB-C to HDMI Adapter - 3-in-1 Type-C Converter Cable for MacBook Pro, MacBook, Mac Pro, iMac, Chromebook, and USB 3.0 Type-C Devices (2017/2018)
13 Review
Cable Baseus Cafule USB - Lightning, 1 m, black/red
26 Review
USB to USB Type-C adapter
18 Review
Logitech HD Webcam C270: Crisp 720p Widescreen Video Calling & Recording (960-000694), Lightweight and Portable at 3.15 lb.
192 Review
π₯ Logitech C270 Webcam: Crystal Clear Video and Superior Quality
183 Review
Apple AirPods Pro MagSafe RU Wireless Headphones, White
159 Review
Enhance Your Visual Experience with Logitech C260 Webcam
78 Review