Cultivating the habit to solve the problem themselves. 
While troubleshooting with their do-it-yourself projects, kids tend to imagine innovative ways. Slowly it becomes a habit. Which helps throughout their lives.
Train the attention span. 
When a child is busy with the construction of a small project, they are at their best. The reason is; improved attention span;
Learn to accept failure and try again. 
Tinkering can not always go right. Sometimes a plan may fail, and a project may not work. They tend to accept it and try again. This learning will help them to cope with the challenges and odds of life.