Does any operating system or commonly used program report file sizes in terms of 1 GB = 10^9 bytes? As far as I know they all use GiB and MiB, whether they call it that or not.
$ dd if=/dev/zero of=/dev/null bs=1M count=1K
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 0.157131 s, 6.8 GB/s
My favorite file manager, Thunar, reports file sizes in decimal units. Not sure if it's distro-specific, though.
Many other programs, like 'df', have a switch (--si) that turns decimal units on or off.
I suppose I should've said that up until five years ago, nearly everyone was using powers of two for file sizes. And Windows/Mac never used the correct prefixes.
It's a tricky topic and as Raymond correctly points out, giving people a term that they don't understand probably serves little to no good purpose.
Of course, aficionados of RFCs will know that "octet" is (or at least was) the preferred term for "byte" in IETF documents as well. I don't think this is because the RFC editor was secretly French, although i'm sure he was thoroughly classy; presumably it's because early RFCs were written in the era when the byte had not quite settled down at eight bits, and needed to be unambiguous.
$ df -k /
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda3 151798672 47602008 102615608 32% /
$ df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 145G 46G 98G 32% /
$ df -H /
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 156G 49G 106G 32% /
$ df --version df (GNU coreutils) 8.22
ls has -h/--si/-k ...
$ ls -h -l /proc/kcore
-r-------- 1 root root 128T Apr 6 19:02 /proc/kcore
$ ls --si -l /proc/kcore
-r-------- 1 root root 141T Apr 6 19:03 /proc/kcore