It's not much fun having to restart a massive level because you couldn't escape the path of three randomly moving blobs.. Even if there is a pattern there, buried somewhere, it's deeply unfun to try to discover it, especially when the penalty for failure is so high.
It's also annoying when turning makes a tile you've not stepped on non-traversable because the a 90 degree turn can cause the trail to extend backwards from your position. I wonder if the whole movement system wouldn't work better if it was grid-based? That way squares could be clearly understood as used or not, and it would also make turning corners much less janky.