I agree that complexity doesn’t imply capability. However, in general they are different architectures which cannot be readily compared. Saying a neurone can only do signal integration from dendrites is like saying a computer can only add 0 to 1. The reality is those dendrites are spatially arranged and may perform computations before reaching an action potential. Also, neurones are still cells and can change structure/position as well as gene expression, which may (or may not) impact on processing over a longer time interval.