Not quite as insane as it first sounds. Soy as xrayflyer is suggesting purchasing MVCI points, not a timeshare unit. This follows the same logic as buying a single share in some corporations in order to take advantage of stockholder retail discounts.

However a single share in any corporation is the only sunk cost of ownership, indeed the share pays back an annual dividend so whatever the stockholder benefits may be, there's a clear benefit to owning a share in the form of dividends. The problems with the MCVI idea are firstly whether it's actually possible to buy just a single MVCI point, and even if it is, it's effectively unredeemable for stays and is subject to an annual "maintenance contribution charge", so unlike the stockholder who gains some retail advantage AND gets an annual dividend, purchasing just a single MVCI point to access the (debatably) better value 5-night Travel Package costs you in annual fees. You end up owning an unredeemable, unsaleable point that costs real money annually for life to keep hold of just to enable (debatably) better value Travel Package redemptions in Marriott Rewards, a program that's earmarked for replacement within 12 months.

Not quite insane, but close.