It's much easier for techs to work and maintain the valks when it's in Fighter mode, panels are accessible and you don't need ladders and extra panels to reach folded areas. This is probably why Fighter mode is the preferred configuration when pilots comes to land, and take off. Unless of course, valks require zero maintenance which I find hard to believe. Again, I prefer to think them as tools of war and not magical rainbow eating super robots.
Not sure why I am responding rationally to this guy, I must hate myself.
On to the topic at hand, I wonder how much die-cast would be used as this valk is quite bulky.