Why is there horizontal and vertical spacing tokens?

[tombohub]

in token docs: https://react.fluentui.dev/?path=/docs/theme-spacing--page

there are same values for spacing horizontal and same values for spacing vertical. What's the reason behind and not have only one spacing?

[khmakoto]

The reason is that different themes could have a different ramp of values for horizontal and vertical spacing. We do not have this in our themes but realize that is something that could be needed in other themes/later on, so our token infrastructure allows for it.