You can just get another re-keyable lock for any added later locks or replacement lock sets. It's not rocket surgery and one of the reasons why you use re-keyable locks. And if you lost a key, just have a new key made. It's cheap and quick. So you are still only needing one key per user. My key ring has a remote for my car, a post officebox key, (they do not deliver my mail to my house), and one door key to the house that has 3 locking doors. The car remote is by far the most annoying thing in my pocket.

Look, we all want to be part of some cool kids club. I want a new 3D printer because despite my trusty old bed-slingers working flawlessly, I would like a shiny new enclosed Core xy printer so I can be as cool as everyone else with a printer. And if I'm not careful, I can have the same problem with shiny new pocket knives at times. Same thing with digital homes. It's driven by the cool factor rather than any real necessity. So go ahead and connect everything you want. But at least admit to yourself that probably half the reason you do it is just to be a cool kid.