Also, netdecks in casual work because people want gold, and to train with their netdecks. So why would be that appealing to create each week a deck wich you can't train enough to try to get it to legend (or to see if its playstyle fits you)? If you can netdeck for tavern brawl, why is it better than netdecking in casual? At the moment we know nothing about the rewards of this mode out of the launch event (except the dailies and 3 wins 10gold thing). So, at least as long as it is'nt more rewarding than casual mode, why would you netdeck a tavern brawl when you can surely netdeck something better and more solid in casual?
Time will tell, but at the moment I have a good feeling about this.