It isn't the best way to do it as far as effectiveness goes but it it is pretty good, especially for web browsing. It is the easiest way to do it on my iOS devices (as a fake VPN profile) and can be switched off in a corner case where I need to access something it is filtering out.
It isn't as flexible or powerful as other methods, but it is very simple. Tools are all about how you use them. Ignoring them isn't any better than suggesting them.
I know the YouTube ads is getting more complicated now, but it's just simple example. Another is hosts file/DNS blocking will remain the blank space on web page, but this one will not.