It was a good idea, but the risks outweighed the worth in many customers' minds.
Since launch, Windows 10 has offered to share stored Wi-Fi network passwords for others in the general vicinity, allowing them to automatically login without having to actually know the security credentials. Configuration for this feature was granular enough to allow users to prohibit access to stored passwords except to contacts from Outlook, Skype, and Facebook. Essentially, the idea was that by keeping the passwords hidden and only allowing “friends and family” to have automatic, behind-the-scenes, access, it would better protect the security credentials.
Microsoft held fast to this feature despite concerns and complaints over privacy and security. But, as of Windows 10 Insider build 14342, this feature has been deprecated.
According to a build 14342 announcement post by Gabe Aul…
We have removed the Wi-Fi Sense feature that allows you to share Wi-Fi networks with your contacts and to be automatically connected to networks shared by your contacts. The cost of updating the code to keep this feature working combined with low usage and low demand made this not worth further investment. Wi-Fi Sense, if enabled, will continue to get you connected to open Wi-Fi hotspots that it knows about through crowdsourcing.
Essentially, the telemetry data collected showed low usage and low demand. It’ll be interesting to see what further features will be taken out of Windows 10 based on consumption.