The nexus 7 needed more roms, plus it's a really cheap device to acquire.
Just like the Pixel / XL phones, the Pixel C doesn't need much "IMHO", customizing from stock roms works really well. If you need any more mods, you can just install that kernel and or any alternate launcher/app and tweak it to your needs.
As with my Pixel Phone, I hardly even need to unlock bootloader, nor root it or the Pixel C. I haven't even perm flashed TWRP in ages...
Pure Nexus, Remix OS and Here's AOSP if you want to build https://forum.xda-developers.com/pixel-c/general/pixel-c-supported-aosp-t3285995