Because DNS based adblocking goes further than ads blocked in the browser. Its also effective in mobile apps, and other devices such as Smart TVs where it is no

Because DNS based adblocking goes further than ads blocked in the browser. Its also effective in mobile apps, and other devices such as Smart TVs where it is not possible to have uBlock do the filtering. I agree its effectiveness is wearing down as ads are served via the first party domain, but it still does make a difference.