Notwithstanding a discussion on proper gain staging, I can think of 3:
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You want to preserve any transients that exceed the 0dB TPL.
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You print a final mix but might want to add processing at a later time.
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You exchange stems with others using 32 bit FP systems.
One can also argue about the S/N quantization being less audible in a 32 bit environment or that the amount of data available for dithering or in-line processing contributes to a “fuller” sounding product but those are discussions based more subjective than empirical.