I don't know anything about the job bank, but in addition to using it I would look on Indeed.ca, and I would also look on the provincial web sites of places you want to live (for government jobs).
When I first landed in Canada, I was excited to find some sort of online job bank in various Service Canada offices -- that sense of imminent success lasted for about five minutes . . . I got my first professional job in Canada by identifying about 6 cities with decent job markets within a long day's drive of where I was living (they were Calgary, Edmonton, Regina, Saskatoon, Lethbridge, Medicine Hat, and Winnipeg) and checking the specific job pages of appropriate organizations weekly. When I finally got an interview, I attended in person, and told them that my wife and I were already in the process of moving there (mostly true).
It probably differs a bit by profession, but I wouldn't put much faith in anything where you upload your resume so employers can find you.