Rehearsal class also had another name other than the class of lunatics. It was the class of commoners. It was named that way, because everyone attending the class was a commoner.
However, "The class of commoners" also had a negative connotation amongst the Nobles.
Commoners had no titles, which means they had nothing on themselves other than their life. Nobles, in the other hand, had titles, prestige, territory, assets, and many things on them.
If they died, they would leave so many things behind, unlike commoners. Due to this, in their opinion, commoners equals to lunatics. Because they had nothing on them, they weren't afraid of death.
While the students of Rehearsal class were indeed not afraid of death, all of them were irrefutably talented. Talented Mages could easily flourish. Therefore, all of them had wealth that exceeded a Baron's. The only thing they didn't have was a title.
