I film at ton action sports, snowboarding, snowmobiling, motorcross, ect.. The advantage of having the controller is when you are going to by piloting while tracking a subject and want to be in control to change angles, shots, ect while the action is in progress. It's also nice to have it to catch some quick scenic shots. Thing I do love about the controller is you can fly directly at an object and drone will navigate around it. I get some really cool tree shots and close fly bys of objects doing this procedure.
For me, the 90% case is filming myself/friend so either of us has beacon, then I use phone to land or change the shot. This is the throw it in the air and forget about it scenario. When I'm out in the backcountry with snowmobile I have storage to bring the controller so it's a no brainer to have it, but when space is a commodity like when I'm filming motorcross, or I'm splitboarding and I just want a small backpack then the controller stays at home. Honestly the controller kinda sucks if your used to the precision of the Air 2 and range is poor. I think you could do without it, especially if your already packing Air 2. I also have Air 2 and it's far superior for cinematic shots.
Couple of examples:
1. This is shot with addition of the controller. At one point the drone spins radically loosing subject, so I regain the shot by jumping to the controller then of course grab some scenic shots while I'm standing on top the mountain:
2. This one I'm filming high alpine motorcross, just beacon and phone in my small backpack which you can see in couple shots: