I knew I was pretty much throwing money at nothing when I was furnishing the Core City house, and I think I have some suggestions that may entice players to not just kit out the basement for crafting.
1) House overall grants buff for visiting
In the dangerous Underrail, wouldn't owning your own house, with full amenities and security, grant you a little bit of peace of mind? I suggest that a small buff, scaling with how much the player has filled out the house, to something like Resolve and Fortitude. The bonus would get bigger the more stuff you have, but not necessarily with the quality of the stuff you have (what type of couch would be up to player, all would grant the same bonus). Most of the furniture (and the security quality) would grant small 1-2% resolve bonuses, only stacking to maybe 15%. Stuff like the broom closet and upstairs toilet, and maybe bed would grant fortitude bonuses (improved hygiene!). I'd imagine the buffs themselves would last similar to food, perhaps with some furniture (like shelves) making the buff last longer rather than improving it.
2) Workout Room Buffs
These are more specific; depending on which machines you've bought, allows you to work out and get some sort of ability score buff. I think the easiest way to implement this would be to make the items in the room interactive. Using them procs a use time like hacking or lockpicking (could use unarmed animations for the punching bag!), and you would then get a debuff that reduces whatever ability scores for what workout equipment you have (Con for dumbells, Str for weight bench, Agl for punching bag) for a short amount of time (you're tired!), that changes to a +1 buff after it expires. Would last a bit longer than food.
3) Kitchen Improvements
Far be it from me to ask for a cooking system (would require a lot of extra items to be added, although integrating it into the crafting system wouldn't be too hard), I would like the ability at the very least to cook raw hopper meat into steaks. Another idea is adding a grocer vendor, who delivers you food for a price, but that might be a little indulgent.
4) Story Trophies/Events
Maybe, when you become Invictus, you get something? Same for perhaps finishing different questlines; a Protectorate medal, some good Free Drones graffiti for completing those questlines, some indication of who you worked for to earn the house...
Further, maybe some events? CAU/Free Drones assassins for completing the opposing questline who stage a home invasion (rewarding your security purchases!), perhaps a mob of fans of the Invictus that you have to disperse to escape the outside of your house. I really liked the situation with the hobo, kind of sad I scared him away; it would be fun to see more like that. Also, inexplicable wildlife infestations are never always fun. Maybe interacting with the mop in the broom closet cleans up the corpses?
So those are my suggestions for the house. I've had a riot with this game, regardless of my inexperience with the genre.
