Each key piece of the control's style is surfaced as a simple color property. This leads to a unique set of style properties for each control. For example, a Gauge has PointerFill and PointerStroke properties, whereas a DataGrid has SelectedBrush and MouseOverBrush for rows.
Let's say you have a control on your form that does not support ClearStyle. You can take the XAML resource created by ClearStyle and use it to help mold other controls on your form to match (such as grabbing exact colors). Or let's say you'd like to override part of a style set with ClearStyle (such as your own custom scrollbar). This is also possible because ClearStyle can be extended and you can override the style where desired.
ClearStyle is intended to be a solution to quick and easy style modification but you're still free to do it the old fashioned way with ComponentOne's controls to get the exact style needed. ClearStyle does not interfere with those less common situations where a full custom design is required.