Fuchs said:

Why would you care about weight if you don't intend to move it much?
The price is much more important.
Good question. Maybe for consealment reasons (if bigger weight means bigger size) and cross country mobility questions ...
What price is right price? Some occasions quality triumphs quantity.

A container full of missiles is expensive enough to actually force an army to use it only at high value targets - and to avoid its loss.
The same thing can be said about other expensive stuff. You destroy your tanks, chopters etc that you can not evacuate. Last link with article about IMI rockets says that this is affordable at platoon level. My logic says that this must be cheaper than MRLS fire. Or not??

It mus not be left behind, even if broken communications or other factors prevent timely use of the missiles before their position get overrun.
If you work out TTP that says "Abandon container and swith to another one, you leave it." How destroy it is another question.

It makes sense to think of this as a container on a truck - a mobile launcher.
It depends how your forces control the battle space. Did Hezbollah drive around with their rocket plaforms during 2006 war?