Why did the Italians used rivets to hold their WW2 tanks together?

I've read somewhere Italy's tanks in WW2 would pop open whenever they were hit by a shell because they were held together with rivets instead of being welded. The rivets were weak points that led to them splitting at the seams if they were hit. So, why did they choose to build their tanks that way? Did they not do any testing to see how their armor would hold up?

 

Maybe because it is cheaper than being welded?
While Italy was one of the "great powers", their industry was relatively weak compare to others in Europe. Maybe they simply don't have the manufacturer capability to mass produce tanks if they choose more complex/expensive ways to produce them?