because you can then spend all of your spells making money. Just because they are an NPC doesn't mean they can't use their resources just as intelligently as the PCs could. Just at level 4, same one required to cast scry, i can see a few spells that would allow him to make the money back. If he hits level 5 spells then he just became the greatest sculptor ever, wall of stone = infinite stone and stone shape = all but detail work done. Wall of Ice, hmmm he can chill the towns water supply every day and make the people happy for a few gold from the town. Locate object/person for Tim's lost and found service, its a real bitch playing hide and go seek with this guy. hell he could open up his own BBQ place and use wall of fire or polymorph into a pyrohydra to cook large amounts of food with, he is a NPC as you pointed out what the hell else is he going to do with his spells.
Money is never an issue in D&D once spells get involved. Some tricks just require a bit more thought and sometimes a DM that sees the value in creative thinking. I admit i treat my NPCs different than most, they are treated as full fledged people that just aren't played by one of my players. The NPC wealth table assumes they sit on their ass most of the time, while they might not adventure they surely can find ways to make money that are just as lucrative. a quote from my bosses old commanding officer "if you want to know the easiest way to do something ask the laziest person you know how they would do it."