Here's the logic.
You buy a Sniffing Set. The odds are reasonable you're going to end up buying a full-size bottle (statistically, most people do). So rather than take two steps, why not just take one? The Bundle allows you to do that. And it saves you $40 in the process.
When you buy The Bundle, we'll send you a Sniffing Set and a $125 voucher for a full-size bottle (the latter by email). That voucher is good in perpetuity (read: a long time). So when you've had a chance to try out all the scents and find your favorite, you can use your voucher and get your full-size bottle. Easy peasy lemon-squeezy.