Car insurance probably would not cover the machines if anything happened to them there (including theft), whereas the movers are supposed to have insurance. Be very careful how they list them, however. I have found through a number of moves that there are unscrupulous people who will make up a long list of bogus scratches and dents for anything they think might be valuable. They know that in the frenzy of moving, and while they have several people working in different rooms, it is very hard for you to monitor everything at once.
Computerized things like to be cool, but I think that's mostly a factor while they are running. It might be that the plastics would be more vulnerable to high heat than the chips. If the machines are closer to the bottom and center of the pod other items around them will provide some insulation. Keep in mind that these machines were probably shipped around the world in pods before you got them!