40% of visitors abandon a website if it takes more than 3 seconds to load. You will be losing many customers if you won't make your website very fast. You can read more about consequences in reports such as https://blog.kissmetrics.com/loading-time/.
The theme is already optimized as much as it can be so to make your website very fast you only have to configure the things that we can't do for you (usually install a caching plugin and configure a CDN).
- All images are resized to the correct sizes and the correct images are served for each device and screen type in each context.
- WordPress and this theme can handle even large shops but if you're expecting to have more than 2,000 products and significant traffic you will most likely have to have in-house developers and further customizations made to WordPress, WooCommerce and this theme.