Actually the authors did address costs - cost of mattress €450. No benefit, however, was demonstrated in this trial because it was underpowered so we think the answer is CAN'T TELL.
Were a larger trial conducted to confirm that the results in this trial were not just a chance occurrence, we think that the benefits would be worth the cost.
Download a completed crib sheet for this paper here.
Now, have a go at the guided critical appraisal quiz to text your knowledge!