the only real advantage is that it cuts down on time spent on brew day. however, you dont want the temp to drop as low as mine did.
I knew I would only have a couple hours on sunday to brew, so I started my mash saturday night.
I used my cooler mash tun. I doughed in with 3.5 gallons on a 10 pound grain bill, mixed and closed the lid till morning.
The next morning, I simply started my vorlouf process as if I never left. I sparged as usual, I typically only raise the grain bed to about 165 or so.
I don't worry too much about mash out most times.
Tv, check this out.
Shorten your brew day with overnight mashing | fermentarium
there's also an article in BYO that I read, might try to google it.
I know others have done this, but they kept their mash temps up above the 'Danger Zone' of sub-140 degrees, hence the name of this brew. from what I understand, thats about when the uglies can make themselves known.