Because
A - cheaper
B - easier
C - some aren't as picky
D - known quality of company
For instance, I'd happily buy from there, if the bat is a price I am happy with and I trust the quality of the batmaker.
Salix, for instance, I would buy blind from here.
There are a lot of people who want to pick up their bat and wave it around before use, but that doesn't prove quality or that you'll be comfortable with it when you are starting to get a bit tired when batting.
Some people then just think that higher price = better bat and pay for what they can afford.