People have a misconception. Condon wasn't acquired because he is a great player, or even because he is better than Andrew Hammond let alone Craig Anderson.
He was acquired because the Senators have had to keep 3 goalies up in the NHL in order to allow Anderson the ability to leave at will and not leave the team hanging with only 1 goalie on a game night. With Hammond injured 2 of those 3 goalies were prospects who should be in the AHL.
Now the Sens have been able to send O'Connor down, and when Hammond returns Driedger can get sent down. Condon is starting tonight.
If he ends up being good, it'll be a pleasant surprise. He was the only goalie available with NHL experience that is a UFA next year, makes league minimum, and would cost next to nothing trade wise. That is why they went with him. Other goalies potentially available would cost too much money wise to pay, and asset wise to acquire.