What changed

The SeekBar preferences are replaced by List preferences.

Old	New

Why

Seekbars are not correctly styled in the new Metarial Design themes, because they are legacy
It's does not adjust the color theme according to the application-wide theme. So this change could be a corner stone of future application theme changes.
According to the MDC spec, sliders (the precedents of the legacy seekbars), are supposed to

Sliders allow users to view and select a value (or range) from the range along a bar. They’re ideal for adjusting settings such as volume and brightness, or for applying image filters.

They are not supposed to present a multi-choice question.