I probably don't understand the excitement over this option to upgrade walls using food, but, I'll probably not push my views on this topic
Just my observation: the introduction of helicopters has invalidated the importance of walls. With helicopters flying over and shooting over walls, it probably matters less how upgraded the walls are.
I had to attack a maze layout in war, and I was surprised how manageable it was with helicopters in my troop mix.
To helicopters, walls don't exist
Just something to think about...
Cheers and happy gaming!