Somehow I tend to think that Big Mind Seminars, for all their cost and hype, may be a touch more useful that the coffin ritual. But maybe it's just me..
My understanding is that Genpo Roshi was trying to reach out to a particular sort of public with the Big Mind show. And quite possibly for entirely noble motives. I certainly haven't seen any evidence of him driving around in RR and buying big holiday houses.
And as far as I know regular practice at his centre in Salt Lake City is still very accessible for the average Joe wishing to take "the slow and steady" path.
In any case, Big Mind only claims to show a glimpse and serve to entice people to take up practice in earnest.
As for the coffin ritual, yes, if the person involved takes it very seriously and deeply, then it can be somewhat transformative perhaps. Still quite a bit of work tends to be needed to achieve transformation. Sometimes a person has already done a lot of work and a ritual can seal that work and imbue it with confidence and luck. On it's own, it pretty feeble though...
Reminded me of this :
The later Middle Ages saw the growth of considerable abuses, such as the unrestricted sale of indulgences by professional "pardoners" (quaestores in Latin), who were sent to collect contributions to the project. In many cases the preaching of these, out of ignorance or shrewdness, went far beyond dogmatic teachings; some of them even dared to promise that the damned would be released from hell. Permission began to be granted to Catholic kings and princes, particularly on the occasion of Crusades, to retain for themselves a rather considerable part of the alms collected for the gaining of indulgences. The most well-known and debated question is the indulgence granted for building the new St. Peter's Basilica in Rome.