This is not a problem with splice per se, this is N+1 problem with treating network as "file socket" per Unix classic idea "everything is a file". It is crazy to consider that writing to a TCP socket over wifi with 1001 reasons for failure is similar to writing to the local memory or hard drive.

Unix began when "networked computers" were sitting in one local network wired in a stable manner with patchcords. Then, latency of communication over the wires was no much different from writing to a local magnetic tape.

Today those latencies diverged dramatically. Your machines talk over radio, with multiple hops between cities and different providers, while local storage pushes terabytes in seconds. Trying to "splice" those two for latency gains is kinda crazy. And so are networked filesystems.

Git / Dropbox are much better approaches: you have your stuff on both ends and sync up content explicitly, without trying to provide interactive abstraction of having data locally while it actually isn't.