BAT assumes that users and publishers are willing to compromise to avoid the supposedly detrimental effects of ad blocking. Some media corporations already threatened to sue Brave for replacing ads, which shows they'd rather lose ad revenue to adblock than get involved in a new cryptocurrency. To people not familiar with cryptocurrency, Brave just sounds like a cash grab.
Apparently users will be rewarded with BAT for viewing ads, so there's the incentive for users to opt-in.