patterns have their use cases and none are universally useful. sending down some extra data via a script tag is good for a few things... having data ready to render without the overhead of loading corresponding elements into the dom. if the server already has the data it would be wasteful to make the client call back later to retrieve it again. of course it's a trade off, sending unneeded data is wasteful.

maybe the data is ephemeral, maybe the second call is unreliable (mobile), maybe the server memory is limited and dumping the state is better than holding onto a session.

what specifically are you trying to manage? what are the use cases you're trying to deal with

starting with a library before you're solving a specific problem is an anti-pattern IMHO

clojure/script make it so simple and easy to solve problems that importing a library ends up adding time for me

because i spend my time learning the library instead of solving the problem

...obviously that's not universally true... i wouldnt write my own json parser or ajax library for example

but how you manage your business data is not something that can be imported (again IMHO)