Thin vertical scrollbars such as those in the Steam client are a usability nightmare. Why do designers still use them? [closed]

1. Why are vertical scrolls are preferred to horizontal scroll?
2. Why is the scrollbar important?
3. Are scroll bars necessary?
4. Is horizontal scroll accessible?

Why are vertical scrolls are preferred to horizontal scroll?

A study presented at WWW2009 (PDF) found that users preferred vertical scrolling because they were used to it as opposed to horizontal scrolling and some pointed out that horizontal scrolling because it "forced them to move their eyes vertically up and down the full height of the screen", which isn't the case with ...

Why is the scrollbar important?

The sole purpose of a standard scroll bar is to enable the user to generate scrolling requests for viewing the entire content of the client area.

Are scroll bars necessary?

A scrollbar is needed in instances where there are a lot of items in a dropdown menu. The general rule is that only 6 to 10 items should be visible in the dropdown.

Is horizontal scroll accessible?

It presents challenges for accessibility.

A page element with both horizontal and vertical scrolling can disorient, and is difficult for people with motor impairments to use.