Booking Sticks To A Traditional Breadcrumb After Rejecting A Multi-Dimensional One

In the control version, we see a traditional breadcrumb which simply shows the depth of hierarchy (geography) along with where a user is in. The breadcrumb also allows moving backwards to any of the previous levels by clicking on the links (Home, Canada, Ontario, Toronto, etc.) Classic stuff.

The B variation also had this functionality, but additionally, it displayed a secondary category (stay types) for each geographic level, turning this into a two-dimensional breadcrumb.

Why might have the B version failed? There might be numerous reasons and I'll try to list them out here.

For one, perhaps the B breadcrumb added way too much cognitive complexity by displaying numerous "Hotels" links everywhere. If users started searching by their preferred geographical context, the added stay types might have added confusion. While clicking on any "Hotels" link, users are forced to make a double choice (geography + stay type) with a single click. 

Secondarily, this approach also diluted the greater clarity of the traditional breadcrumb that answers "where a user is currently in".

Finally, perhaps because the conventional breadcrumb is so widely used across so many other sites, users might have been expecting the simpler approach. 

Of course, let's keep in mind that trying to dissect and explain experiments post-hoc should be considered more hypothetical than definitive. It's easy to point fingers. Seriously, hats off to Booking for trying something more riskier for us to learn from. :)