CaptainSpaceman

Please ignore the other two commenters…..

Adblockers block ads at the user level, meaning you have to manage the adblocker for each device in your ecosystem.

PiHole and similar DNS based ad blocking technologies OTOH block ads at the network level and only needs one install location to manage content for all devices you have on your network.

This means with PiHole you can have one set of custom rules that block all ads at the network level by using a set of pre-loaded and customizeable DNS blocklists. OR! you can install Ublock on 2 devices in your house and let the other 7 devices that have no access to adblockers (like IoT devices) be subject to the atrocity that is modern advertising.

Additionally, adblockers in browsers can eventually be shut off. See: Google Chrome and Ublock Origin.