I must admit I don't use Pluto a lot myself ;)
But since Pluto itself is barely ever used inside other code, we could consider it a REPL utility, so I'd say it's pretty safe to add it to the global environment. Pluto will start a separate environment for you anyway once you launch it.
René
Great blog, Matthijs Cox! What do you recommend for
Pluto? Installation in the global environment (because it is used in multiple project environments) or installation in every project specific environment? Like to read your thoughts on this.