I now run BGP on my home network, and I want to be honest about why: mostly because I could, and partly because it's the best way I've found to actually understand the thing I get paid to reason about.
The practical excuse is route announcement. I have a couple of services I want reachable on stable addresses regardless of which box they land on, so each node runs BIRD and announces a small subnet to my router, which is also speaking BGP. When a service moves, the route follows it. No static routes to hand-edit, no DHCP reservations to babysit.
It is wildly over-engineered for a one-bedroom flat. A static route would do everything I need and fit on a postcard. But I spend my working days debugging why a prefix isn't being accepted somewhere, and there is no substitute for having watched a session flap on hardware you own at two in the morning. The lab makes the abstractions concrete.
The setup is a single private ASN on each node, eBGP to the router, and a deliberately paranoid import filter so a fat-fingered config can't announce something daft like a default route into my own network. That filter has saved me twice already, which tells you something about the kind of mistakes I make. Worth it, even if "why not" is doing a lot of work in that justification.