What benefits each astro type gives?

There are astros that give you more economy or construction/production.

Crystallines are the best to economy; moon give 3 econ to your cristal processor structure, and planet give 4!

Metallic in the other hand give you more metal, so it make your base production and construction way faster. Moon give 4 metal and planet 5 metal. A metallic planet can easily reach production 600.

Check the Help about Terrains page to more details.