What I appreciate about Best Buy and brick and mortar is that I can see and touch the merchandise. I can browse the rows of movies till I remember the movie that I really wanted, even though it came out 30 years ago. I can't do that online very well. Also, I can see a closeup of the electronics, instead of relying on a postage stamp-sized image online. I don't always recognize whether I need 1/8" in or out or what A/V outputs and XLRs I'll need, but I feel more comfortable being able to see those interfaces on the product in the store. And then I can make sure I buy the right cables.
I will miss Best Buy when they go under.