Impractical for campuses to become temporary shelters? (7)

I believe the answer is:

useless

'impractical' is the definition.
(thesaurus)

I don't understand the remainder of the clue.

(Other definitions for useless that I've seen before include "Good for nothing" , "Ineffectual" , "nohoper?" , "Having no beneficial function" , "Having no benefical function" .)

I've seen this clue in The Guardian.

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