Step-down crimping connector is just a little smaller than set-screw connector, and the latter is - probably - same tall as mini-ground bus.
This is all new to me, but it looks that in-line connectors - butt or set-screw - are difficult to attach to anything inside the box, so they have to be wrapped in insulation or shrink-tube or they may short to each other. There will be 2 lines in each enclosure.
Edit - PS: SMK, you are right. In a small enclosure like
3/4" conduit body there is no room for anything but inline connectors.