using standardized public smart contract platforms sufficiently abstracts the level of development needed to maintain these clients and accounts, since the platform and other nodes handle that. the alternative is some other cloud platform, where you have to write everything from scratch and do all the typical dev ops and system design and pay for it all, in smart contract platforms you deploy once and there is unlimited free reading bandwidth and your users pay to write to your application. until that is seen anywhere else, the blockchains will continue attracting developers and their audiences forever

interfacing with liquidity pools and the rest of the infrastructure on smart contract platforms is also part of the benefit

it doesn't matter that you could do this 20 years ago, the frictions towards doing it were too high

not having an ethos of decentralization aside, the reduced friction does rely on the permissionless, transparent, and at least distributed aspect of the public blockchain

they can interact with blockchains that way, you can choose not to use it while still using blockchains your way. who cares if they are using blockchains for a centralized product, organizations have been doing that for 10 years which means the fact you're only triggered now means the permissionless aspect of blockchains is working