If you have a specific wine you want to buy
Generally speaking, I don't. If I do, I know where I got it in the first place, and can go back there.
Trying to buy each item I might want from its originating winery is A) way too much work and B) almost certainly not going to be a bargain.
I'm a browser. I want to "walk up" to the Alsace section, for example, and see what looks good and is a good value. This requires that someone who knows what he/she is doing has purchased interesting items at a good price.
Bottom line, there are so so so many wines out there that starting with what I "want" in the abstract tends to be unproductive. Much more effective to start with what's actually available for purchase.