I upgraded my iPad to a USB-C version and discovered I couldn't use my 1st-gen (Lightning) Apple Pencil with it even though it's compatible -- because I first had to buy a special female-female USB-C<->Lightning dongle just to be able to plug it in to pair it. (Even though I can keep using my Lightning charger to charge it separately from my iPad.)
Moving from Lightning to USB-C hasn't been too bad for me since I use wireless charging with e.g. my Lightning AirPods. But the transition is a huge pain. Because of weird cases like the Pencil, it's not even enough to just have a USB-C charging cable and a Lightning charging cable.