Probably there is a thread with this topic, but I’m on my mobile… So searching is not pleasant. Overall they are great for two types of missions:
- evacuation - where you drive fast to target, you take control of target and you evacuate again fast enough. Scavenge mission fall also here. You just need to get used to how to put items in vehicle’s inventory (soldier needs to be in the vehicle and then he need to drop items from his own inventory - they go to vehicles inventory instead of ground). This way these missions become a lot easier.
- base defence missions (not haven defence) - you can have any number of defenders there so vehicles don’t count against soldier limits and they can support with defence. Of course this is mostly not necessary as these missions are easy as piece of cake, but sometimes you can’t get there with soldiers, and vehicles still can defend your base.
Overall they are also great at the beginning of game when your soldiers are quite weak and such vehicle is more powerful than any combination of 3 soldiers. They also can fill the aircraft when you don’t have enough spare soldiers to create second team.
And they have weapons. Scarab and Armadillo are great at dealing nice damage and taking enemy shots. Aspida is great for supporting team and some paralysis done to enemies. Mutogs are the least useful, but still they can be good melee fighters when you have lack of soldiers and they can deal with most weaker enemies easily.
Edit. Mechanical vehicles combined with technician class soldier equipped with mechanical arms are considered overpowered things in the game.