I've played around putting USB connectors directly on PCBs, and USB-A is way more lenient than USB-C. With USB-A, you can use basically any PCB thickness between the standard 1.6mm and 2.2mm, and it'll work well enough.
USB-C's midplate is specified at 0.7mm, and all of the cheap chinese PCB manufacturers only offer 0.6mm and 0.8mm. 0.6mm is too thin to make reliable contact with most of the cables I've tried: I haven't gotten around to ordering another batch at 0.8mm, but plugging the corner of a 0.8mm M.2 SSD into a USB-C cable, it's pretty (i.e. probably slightly too) snug. Thin PCBs are also extremely flexible, which isn't great for brittle solder joints, ceramic capacitors, etc.
USB-C's midplate is specified at 0.7mm, and all of the cheap chinese PCB manufacturers only offer 0.6mm and 0.8mm. 0.6mm is too thin to make reliable contact with most of the cables I've tried: I haven't gotten around to ordering another batch at 0.8mm, but plugging the corner of a 0.8mm M.2 SSD into a USB-C cable, it's pretty (i.e. probably slightly too) snug. Thin PCBs are also extremely flexible, which isn't great for brittle solder joints, ceramic capacitors, etc.