I have only been in the supplements game for 6 months... I come to stores like this looking for very specific things prescribed by my doctor. It can be very overwhelming to find them in a store full of jars.
I have been to several different stores where I never feel confident that they will have the product I need in stock or that I have received the right thing.
Both of those problems are addressed a the Big Carrot.
Also, they sell Thorne products. These are hard to find elsewhere.
Perhaps others are right about the prices - it's not cheap. But if you value your time and peace of mind, this is the place to come.