In terms of usability, vertical space almost doesn't matter anymore. The vast majority of people have an interface that makes vertical scrolling effortless, whether it's a trackpad gesture, mouse scroll wheel, or touchscreen drag / flick.

Horizontal scrolling is harder to do and less common/conventional (chicken and egg as to why, but it's the reality today).

You might not like the way it looks, but it's clearly better for usability to spend more vertical space in order to prevent horizontal scrolling.