The Leafs may not have the star power on left-wing that they do on the right-wing or at center. That being said, they are still deep there and because the Leafs thought that he wasn't going to be able to leapfrog either of Ilya Mikheyev or Pierre Engvall, they put the newly acquired forward on waivers.
Dzingel being claimed means that as of right now, the Leafs have $366K in cap space. That is a number that can go up however because the Leafs are currently carrying 8 defensemen on the roster. Losing Dzingel to waivers and then trading one of their surplus' of defenders would provide the Leafs with some valuable cap space heading into the trade deadline. Until then, they can potentially send someone down to begin to accrue more cap space.
Dzingel's Leafs tenure ends after 0 games played but luckily for him, had hadn't reported to Toronto yet so he won't have to travel too far from Arizona to San Jose.