Because it's easy and has a million plug-ins... including an e-commerce one that is decent and hackable.
Why wouldn't I?
Ummmm... correct me if I'm wrong... but isn't the goal to have a unhackable site...? JUST SAYIN...
And BTW are you planning to use wordpress plugins to handle the sales and mod shop or w/e....?
There is no such thing as an unhackable site, really... certainly not for the money and time I have to spend on it. At least Wordpress has a million eyes on the problem.
Yes, I'm hacking through WooCommerce at the moment trying to make it dance the way I want it to.
I don't what I'll use for the mod shop yet... but further hacks to WooCommerce are certainly a possibility.
I have not found an out of box solution that did what I wanted... even the expensive ones.