Local names (bookmarks) and autocomplete definitely work for some cases, but they alone without global short names objectively provide worse user experience than what everyone is used to. Couple that with a much larger attack surface for fishing scams and it creates a not very secure paradigm for an average user, onion services proved this point over the years. Also consider that such Bitcoin based system can work in parallel with cheaper randomised domains of Pubky. It doesn’t have to scale enormously, it will create a free market where people who want a short name will have to pay the costs of doing so. As far as I am concerned Nomen would not burden Bitcoin network significantly, so the cost of having a decentralised short name would be the same as the cost of sending a normal on-chain Bitcoin transaction, which seems more than reasonable.