I was just thinking 'guys, close the flap in your Y fronts.....'!
My separate post on webserver speed indicates that WP hosting may need more tweaking that standard, which affects load speed.
I am not a programmer or techie, but my small brain would think that something that is designed to do a job i.e. e-commerce site, would be automatically faster than a site designed for blogging with a plugin. My limited experience of PHP sees a lot more code in WP than in something like Prestashop (which I used when it launched and thought it was slick and fast then!).
HOWEVER, WP/Woo is allegedly used by +5 million sites (Prestashop +300k), hence the bigger fan base.
What you need to bear in mind when choosing a platform and the overall site implementation is that an e-commerce site needs to be more than just an online shop - you need content, data collection etc.
If you just want a shop, get an e-commerce platform. If you have a website and want to sell, WP/Woo is a good option