Might be an error, or the game designers felt that it should be hard becoming a fully fledged wizard. I did a quick check and unless I'm mistaken the dedicated trait doesn't appear on any other career anywhere. So as a GM I'd probably change it to the Wizard trait. Having a trait that doesn't appear anywhere else just seems like an error.
If it's not changed though it only has a minor impact.
As Carcosa said; if you completed the acolyte career and dedicated it you're still only going to pay 0/1 XP to transision into Wizard. Since completion of acolyte is required to change into Wizard (see the Special on the back of the Wizard career card) it doesn't matter there.
But if you want to become a Battle wizard after the Wizard career it does matter a bit. It will cost 1 XP more as they have Arcane, Combat, Elite, Wizard (only one match with Wizard). Then you'll have to pay 1/2 XP depending on if you're a reiklander or not. So if you want all the wizard careers it would be better to move into Wizard Lord from Wizard and after Lord into Battle Wizard, then you wouldn't have to pay the extra XP.