I have many nerdy friends who have been Linux users for ages. But most of them don't know such a thing as Openwrt exists or have never bothered to give it a try. It's a very fun piece of software to play with and can be extremely useful for routing traffic. Wondering why it isn't more popular/widely used.
I've used OpenWrt, DD-WRT, and Tomato firmware on the various routers I've had. I don't think I've ever kept the stock firmware on any router I've owned.
I use pfSense at home now, but I've been considering switching to OPNsense. I still run OpenWrt on a portable router that I use when I'm traveling though. I won't ever buy a router that I can't run open source firmware on.
OPNsense is solid too, better than pfsense.
A portable router when you’re traveling?
A lot of places will restrict the number of devices you can connect. If I connect my router to the hotel WiFi, I can connect as many devices as I want. I also like having a firewall between my devices and the public WiFi. I can run a VPN on the router and have all of my devices go through it if necessary as well.