Do it for core stability, posture, and coordination.
All of the common carry variations are performed holding objects at your sides and walking straight ahead, but this variation does quite the opposite: the Figure 8 Zercher carry.
Rack the barbell inside of your elbows and hold it tightly to the body (yes, it's uncomfortable but shouldn't be painful). Having the weight in front of you forces you to brace your core, maintain optimal positioning, and activate the muscles in your upper back. If you don't, you will get immediate feedback as the barbell will begin to roll off your forearms.
Walking in a figure 8 pattern will challenge your core stability and control as you make your turns. Focus on owning the barbell and not letting it steer you off course as you move about. This becomes more challenging as you add weight to the bar.
Throwing a carry variation into your program will do wonders and you can even do them for a whole workout. Try this variation for time. Do 1 minute on and one minute off for 3 rounds.