But why do you think OpenWRT is better? Because it has a (somewhat clunky and not as feature rich) adblock solution built it?
So does pfSense with pfBlocker-NG which is also another common adblock solution people use.
But for a basic user to just augment their home network with ad-filtering, way better off to just have add a pihole, than to totally replace their router.
Yes, OpenWRT does have an adblock solution. It might not be as shiny as the PiHole but it works. Also, you can buy a decent router for less than you would pay for Pi+Cables+Case+Power Source.
I use a tp-link wr842nd. I even have a Telegram bot on it to interact with it. A Pi would be more powerful, sure, but the router serves my needs.
Although PiHole doesn't need a huge amount of power, it does need seem to need more resources than the average router has, unfortunately - it has components written in PHP, at least if you want the web frontend, and runs some SQlite DBs which might not work well unless your router has some "real" storage attached to it. It's also a pain to get working unless you give it its own local IP address. While it might work, it would be kind of defeating the point of it being "plug and play".
If you have any kind of local server running "proper" Linux (not necessarily a pi) it's pretty easy to run pihole on it though - there's a docker image or you can fire up your favourite other Debian-based VM/container image and install using a shell script.
