What work? Work to maintain it, test it, etc. Essentially, every time a software update is rolled out you do not know for sure if it is going to work flawless on your platform. For a random home network that might be sufficient; for a corporate network not so much.
I know about Aliexpress (and the like), but I don't find comparing Chinaware with non-Chinaware fair without taking that into account as a minus. Not that I wouldn't go that route if I would go for DIY though.
Router7 uses coreboot and a heartbeat to restart the machine if it fails.
x86-64 still uses more kWh than this MIPS machine. The ER-L has 3 ports, allowing physically separated networks. Depending on your setup you can even use both. The ER-X is less powerful and is MIPS32, though does support more hardware offloading (and WireGuard has optimalisations written in C for MIPS32).
