Is that sentence poorly written? I mean the word elsewhere means in or to another place, and before is a preposition of time, not the place.
It would help if we could see the sentence in its original context. It's hard to guess if you need the word elsewhere or not.
However, your sentence looks a little clumsy overall. Would either of these revisions work?
But water plays an even bigger role elsewhere, before it's frozen into those perfectly aesthetic, slow-melting ice spheres or bottled up for exorbitantly-priced sales.
But water plays an even bigger role before it's packaged in expensive plastic containers or frozen into those perfectly aesthetic, slow-melting ice spheres.
The role that water plays elsewhere is a role which it carries out earlier in it's lifecycle.
i.e. it has other roles, and these are not played out here in the topic at hand.
The other roles happen in an earlier part of the sequence of: evaporation; cloud; precipitation as rain or snow, etc.; run-off; capture; bottling.
"before" is a preposition and a conjunction. As a preposition it refers mostly to time, but it can refer to place also in special cases.
In your example "before" is a conjunction, introducing a subordinate clause. See Oald, before, conjunction http://www.oxfordlearnersdictionaries.com/definition/english/before_2