If I'm going to be charged 20 euros whether I succeed or not then for small disputes I may not bother spending the time to submit evidence anymore...
Edit: I see that they have a Chargeback Protection product with costs 0.4% per transaction in which case they "cover the disputed amount and waive any dispute fees without needing to submit any evidence" (another comment by smca)... So cynically that sounds like a commercial tactic to sell that product!