Maybe 'symmetry' isn't the best word. Maybe 'uniformity' is better. But what I mean is, the fins you make most likely are not going to be perfectly flat - they are likely to have nicks, bends, crinkles - like wadding up aluminum foil or a gum wrapper and trying to flatten it out. Also your spacing between fins, offset, angles of alignment are going to vary. These 'imperfections' may give you added air turbulence that the folds would normally provide on a core that was manufactured to more exact specs.
Remember, if your project is a flop, I'm only speculating here. On the other hand, if it works out great, I'll take the credit.
