I'd more alarmed by the fact that they've thrown something new into the mix security-wise than the effect on startup time.

If the system pseudo-random number generator has no problem, what's the use case for not using it? And if it does have a problem I'm sure they would have told someone :)

I just don't know why you add another moving part to the security system if you could avoid it, especially since it seems like a reasonably safe bet that people have had more eyes move over / experience with the alternative.