All Cash Offer, what's the appeal?

[Race Ostler]

I'm fairly new to real estate and new to this site but my question is about what makes an all cash offer so attractive? 

A simple example:

There is a home for sale for $200,000 with three offers.  Two offers are for $190,000 financed (20% down) and the third offer is for $180,000 all cash.

If the seller doesn't need to sell the home super fast, why would someone accept an all cash offer?  I.e. if you don't need the proceeds asap, wouldn't you most likely make more money taking a chance on the $190,000 offer who still needs to officially close on his loan?

Also, for those scenarios where someone does need to sell quick, what is a typical discount that paying all cash can expect vs financing?

Thanks in advance