The problem I see is that someone might assume that since their first step was free (custodial without fees) it will always be like that. And of course you can try to educate later on why self-custodial has a price, but generally people are so used to free stuff that most likely they'll expect it just by laziness and feeling of entitlement. And they might treat the custodial solution as something good enought to keep bigger sums. I don't want to have bad feeling on my conscious later if that gets rug pulled.