The reference to "where their worm dieth not", is evidently part of this same idiom for total destruction - it is inconceivable that there could be literal worms which will never die.
Katika kutaja "ambamo funza hawafi", ni dhahiri sehemu ya msemo usiotumika kwa namna ya kawaida ikiwa ni mamoja na kuangamiza kabisa - haidhaniwi kuwa kunaweza kuwepo funza halisi ambao hawatakufa.