My brother uses a 0 degree for all paddling and doesn't have any issues...

I think the whole theory of the feathered paddle was based around racing. Unless you have 40 mph upstream gusts, I don't think you really need to worry about wind resistance in creeking.

I use a 30 degree and can barely feel a feather on it.

Play boating zero degree rules
Creeking/river running it doesn't matter what ever you are used to is good
So if you only are buying one paddle go with a zero

I think that back deck rolling is harder with a zero degree paddle myself. You have to twist your wrists much more due to the lack of natural feather in the paddle.

Playboating is better I think because both blades are in the same spot all the time so placement is easy for me.

Creeking is a tough call. I have always argued it two ways and I still don't know which one is more critical. If you were to run a drop lets say over 10-15 feet and land with your paddle across the chest, chances of a broken shaft are very high or injury to face, since the blades will meet equal resistance on both sides. A feathered paddle with give on one side releasing the pressure and decreasing the chances of a break.

On the flipside when your dropping a water fall higher than you wanna use a boof on, zero feather does seem to have less shuttle and pull on landing, most likely because both blades slice through the water without the natural twisting that happens when you have a feathered blade.

Doubt it helps, just use what you think is more comfy