Google's proposal is a smear. [1] Most time servers do not use smear. No idea what behavior it may introduce in places where sub-second time is important. Curious if all these bugs [2] were fixed specifically to deal with going backwards.
As far as the computers were concerned, nothing was different.
It would have been better if they would have kept the time on the wire accurate or added mandatory protocol stuff to avoid confusing things for ntpds configured to different leap second handling.
And some things do trade 24/7 (though I wish they wouldn't, one auction per minute during US east coast business hours would be totally sufficient for most US markets).
Leap seconds can be stored and communicated, if you need it you can do the work and get it. Leap smearing, you're shit out of luck, especially if you're a developer and need to deal with systems operated by others.
If you're sure you'll never cross that moment and need to know you're in a smear, go ahead, it's great. Otherwise test yo' stuff with leap seconds and get bugs reported & fixed.