you can do without, but you need a usb/seral adapter, a power supply, some sensors and buttons, very good eyes and a steady hand to solder the stampsize unit on a.. yes, on what ? (hi Charles - hi Dan)
so I am lazy .. and I have some 'old' arduino shields laying around.
another thing I noticed is, that in the hardware integration guide they mention (warned) that you cannot have copper around the ufl connector.
so that's maybe also difficult to achieve without designing a dedicated expiriments pcb breadboard converter