Trixie’s talent is magical items, but suffers from a prolonged bout of Cutie Mark Failure Insanity Syndrome stemming from an incident in her youth that nearly killed her. As a result, she tends to shy away from crafting personal magical items, occasionally letting it vent when she makes fireworks or speccing out her caravan. As a result, by the time Boast Busters rolled around, she was in the habit of goading oversensitive audience attendees into showing off their stuff so she could incorporate it into her act and possibly fill the gap inside her. By the time Magic Duel came up, she was desperate enough to go back to her talent by using it to track down the amulet.
Also, one of the first things she did was use the amulet to acquire a huge quantity of gems from an abandoned mine to build up her wealth. As part of a plea deal that kept her from going to jail, she was allowed to keep a small percentage of the wealth while donating the rest to Ponyville and garnishing any future wages. She also waved her right to sue/prosecute Carrot Top, Bon Bon, and the other Ponyvillians who stalked her across Equestria and only let up when, say, Discord’s Second Reign obliterated her tracks.