Even more ridiculous since a 1.4x performance increase is already incredible news for anyone who makes regular of this.
If someone found a software optimization that improved, say, blender performance by 1.4x people would be shouting praises from the rooftops.
Completely anecdotal but I was able to add my brother-in-law to my Steam family without any problem and he lives about 125km from me.
The requirement is absolutely something more arcane than “same household” and Valve are keeping quiet on the actual specifics. It’s possible that the fact that I’ve been there multiple times and have logged into Steam on their wifi in the past was enough to confirm that this is a place with close relation to me. Who knows though.