Amazon opened its first physical bookstore in Seattle on Nov 2. This is not the first time a pure play online retailer has opened a bricks-and-mortar store. Warby Parker and Bonobos have done it before. But Amazon is the 800 pound Gorilla of online retailing and has steadfastly resisted going offline thus far.

So why did Amazon bite the bullet and open its physical store? Several factors may explain this development. First, despite the phenomenal growth in online retail, a substantial chunk of sales is still offline. People still love to go to physical bookstores and browse books. Second, it could just be an experiment. Amazon may want to test the waters offline given that many pure play online retailers have been doing it before. Third, it could be firing a salvo at Walmart, the world’s biggest offline retailer and its biggest rival, which has made tremendous strides in online retail. Fourth, it may be changing the way brick-and-mortar stores designed. It has designed its physical store with data collected from its online store based on customer reviews and sales measures. Finally, sales of e-books may be leveling or even falling.

Whatever the reason, when the world’s most valuable retailer like Amazon enters the physical turf, it promises to elevate omnichannel retailing to a new level. Let the games begin!