Parameters determine the geometry that will be affected by an action when you manipulate a block reference.
When you add a parameter to a dynamic block definition, grips are displayed at key points of the parameter. Key points are the parts of a parameter that you use to manipulate the block reference. For example, a linear parameter has key points at its base point and end point. You can manipulate the parameter distance from either key point.
You can specify grip size and color for display in the Block Editor. This setting does not affect the size and color of the grips in a block reference.