The computation time can be orders of magnitude worse on a bunch of every-day cases. The computation order that einsum uses needs to be at least greedily optimized (which takes hardly any time). I underestimated this fact before, and it gave me an enormous performance hit on what would’ve been a simple computation.
It would be prudent to perhaps test in numpy at least to see if the default einsum computation order is fine (as compared to the optimized order that numpy will let you use).