Immediacy has value, so if you need something _now_ you will be willing to pay for that.
Also, you have to pay in time and money to go to the store, so you _may_ be willing to pay more to have the book delivered.
In both situations, the way the book gets to you changes the price you're willing to pay.
You aren’t likely to talk to a knowledgeable salesperson at a chain bookseller, as generally they are not big book fans. They just needed a job, and these chains will hire just about anyone who can competently work their POS systems.
I can understand certain independent bookshops having great additional value to customers because their proprietors and the other clerks were voracious readers. However, for Borders/Barnes & Noble/Waldenbooks, and various other US chains, their staff has been generally unable to talk in any depth on books since at least the 1990s when I first visited them.
As somebody who spends a ridiculous amount of time at my local Barnes & Noble store (I work from their cafe a lot, but also come here to buy books a lot), and who has gotten to know most of the staff here pretty well, I would say that this does not jibe with my (n=1) experience. It doesn't prove anything, but the people who work here (the New Hope Commons store, in Durham, NC) are quite often bibliophiles, and/or are very knowledgeable about books and/or quite a few other things. One of the baristas is a masters student in Data Science and always points out to me if some new techie book has shown up on the shelves that he thinks I might be interested in. Several of the employees are also authors in their own right, and I just finished one of their books which was, if not exactly great, definitely at least worth reading. Another lady ran one of the first ISP's somewhere in the midwest back in the day, and knows all sorts of interesting stuff. Amazingly she didn't know about the show Halt & Catch Fire until I mentioned it to her the other day.
Anyway, I digress... the point is just that at this one store, at least, there is a staff of people who are quite knowledgeable/interesting and make it worth coming in, in order to interact with them.
That really changed after a disappointing 2017 holiday season when they laid off close to 2000 mostly long term employees in February 2018. They basically dumped a lot of long-term employees and hired much less experienced basic retail workers if they hired anyone at all. There was actually a fair amount of angst about it at the time particularly among bibliophiles.
A trenchant but insightful review of events from the time: https://audreyii-fic.tumblr.com/post/170886347853/the-entire...