First, the plywood is good quality Baltic stuff.
Second, I wanted it to be light.
Third, in general, I'm convinced that we tend to use material that's too heavy. 3/4" drawer sides really bother me.
As far as this discussion goes, I've put myself at a disadvantage by presenting something safety-related, but I think it's strong enough. We will see...
Wait'll you see the router cabinet I'm designing. All 3mm plywood.