Right now, using the unit B in Zabbix applies IEC binary scaling (base-2), but the UI still shows values like KB/MB/GB. That is misleading as those usually imply decimal (base-10).

There are two standards here:
SI - Decimal prefix where kilo = 10^3 = 1000. Units: kB, MB, GB.
IEC - Binary prefix where kibi = 2^10 = 1024. Units: KiB, MiB, GiB.

Zabbix is effectively using IEC behavior when unit is set to B, but shows the units as SI.
I believe it would be helpful to make this explicit.
Suggestion: Add option in Item configuration to use either SI or IEC. Default to IEC as to not force any breaking changes. Also if setting is IEC, add the "i" to "B" if value exceeds 1024.

This would align Zabbix with SI/IEC standards, and give users control over how values are displayed.

Sidenote: if manually changing a unit from "B" to "iB", Zabbix changes calculations from IEC to SI, so it is the other way around. Since "iB" is not recognized as a special case, so it defaults to SI.