Given the lack of the "middle ground" introduced by this patch, you have (had) a choice between the failure mode of "block for a very long time" and the failure mode of "might generate easily predicted cryptographic keys under certain extremely rare circumstances". You use /dev/random if you prefer the first failure mode.

Edit: The whole situation didn't make sense from a system design point of view (unless you don't believe in CSPRNGs, but then you're basically screwed anyway), but given the unreasonable interface as a constraint, it's conceivable that somebody might have reasonably made the choice to use /dev/random.