Jet Lasers PLE Pro 520nm 70mW

I'm thinking about buying this laser for some general star gazing, but I have a few questions about the options:

1. Is the beam expander worth it? Does it make the beam visibility significantly greater?
2. Manual or Code lock? What are the pros/cons?
3. What is the duty cycle of this laser? Can I run it continously? Would 50 mW have a better duty cycle?
4. How much more operational battery life do the larger capacity batteries give?

Thanks in advance!