Without it we lose another method by which people can develop software without adding to Microsoft's empire. Taking MS's objection one at a time Java isn't really cross-platform.
Different platforms require special tweaks.
As a software developer who has written multi-platform software, I'd rather have to tweak something than redo with another tool to make it run on another platform. Java isn't really open. Sun controls the standard. The pressure mounts daily to force SUN to open it. Java isn't really more efficient.