The idea is to create a base for content types that would have constantly updating texture data. The main idea behind most display types in BS2D is to statically generate as much stuff as possible at setup, but sometimes that just won't work for memory constraints (sprite sheet of every animation frame wouldn't fit in memory) or for content that may not actually be complete (like a streaming swf or flv, or scrolling TLF content etc).
The idea is to create a base for content types that would have constantly updating texture data. The main idea behind most display types in BS2D is to statically generate as much stuff as possible at setup, but sometimes that just won't work for memory constraints (sprite sheet of every animation frame wouldn't fit in memory) or for content that may not actually be complete (like a streaming swf or flv, or scrolling TLF content etc).