I think that it can look similar to smp. Smp, however, will have dots whereas Dermmatch will just be more of a shadow effect.
Of course with smp you cannot see individual dots (it should look like a 5 o'clock shadow with a good smp treatment) unless you are looking for them and have your eyes literally inches from the scalp you are observing.
Also, smp is obviously underneath the skin in the dermal layer; Dermmatch would be applied on top of the epidermis, so dermmatch is more noticeable and shows up better under bright light and won't be subject to the common "SMP Vanishing Act."
I have tried Dermmatch in the past and it works well but it is just not feasible for me to go through the grueling application process every 2-3 days. Plus with Dermmatch comes the constant worry of it rubbing off or smearing/sweating onto your face or clothes, someone's hand, pillow or any other surface that is not your scalp that would make it apparent that you have makeup on your scalp.