DNS Blocking: A Viable Strategy in Malware Defense

Sort of off-topic, but I brought this up in a cybersecurity info session at my organization. I questioned whether it would be viable to block all incoming ads in order to save bandwidth, and also mitigate the possibility of any incoming malvertising attacks. We already do a lot of DNS blocking to begin with, I thought maybe blocking ads through DNS would be helpful.

The response was that it would hinder user experience on the browser, and we are doing a good enough job at blocking malware as it is right now and the amount of effort to block ads would not be worth the return.

I still remain curious as to what would happen if we did block ads company-wide using DNS.