Enlightening; thanks, Matt. And apologies to the list for my earlier inadvertent double-post.

On Mar 29, 2014, at 12:16 PM, Matt Whitlock <bip@mattwhitlock.name> wrote:

> On Saturday, 29 March 2014, at 10:08 am, Chris Beams wrote:
>> Matt, could you expand on use cases for which you see Shamir's Secret Sharing Scheme as the best tool for the job? In particular, when do you see that it would be superior to simply going with multisig in the first place? Perhaps you see these as complimentary approaches, toward defense-in-depth? In any case, the Motivation and Rationale sections of the BIP in its current form are silent on these questions.
> 
> I have added two new sections to address your questions.
> 
> https://github.com/whitslack/btctool/blob/bip/bip-xxxx.mediawiki