Ability to show multiple products on one line in mobile.
I want to be able to display at least 3 columns on my pages when using a shortcode to display product categories. I have hundreds of items in the same category displayed on the same page and having users scroll one by one can be a pain.
Edwin Hamers commented
You understand that storefront, and most other responsive themes, will size according to the screensize it is being viewed on. If you would have multiple columns on a mobile device things would become too small and unreadable.
Plus scrolling on a mobile is much easier then a mouse ;-)