What makes you say no one was using it (my understanding is the opposite), and that most certainly does not lead to your conclusion even if the first part is true.
Just because FB killed it doesn't mean it no one was using it...
The "/s" indicates sarcasm.
Parse's advantage was not only convenience but multiplatform.
CloudKit has a javascript sdk...
Which is based around a HTTP API (also documented by Apple). Not that hard to wrap that in an easily usable SDK for other platforms.