With a centralized service I don’t need a law degree, I can quickly ask an expert what my rights are and understand an option, and there is a (limited and slow, but existant) method to make myself whole in the event of a problem. Each dApp is its own special setup and it can be quite complicated to figure out exactly how it behaves, who to sue if it doesn’t, and who to pay money to find these things out for me. I hope you’ll forgive me for being worried about trusting that with any significant sum of money.