The crypto ad system is their best feature. You get browser ads instead of website specific ads and so any website can get money simply from users using brave. Also you can choose which websites get some of your specific ad money. It feels more like the money being made off of you is also being spent by you. Taking power away from big tech.
I think one issue with this is you would probably have to identify yourself. Many companies would only offer credit card / paypal to pay for the stuff you use. With BAT (or an alternative) you can pay without identifying yourself (more than say IP).