Long story short - KB (/MB/GB/...) is usually a non-issue in most cases given the appropriate context.
When it deals with binary *size*, it's a power of two multiplier in most cases (except in the storage industry...), and when it's about data throughput (such as in KB/s), it's already a lot more ambiguous and needs even more context or an appropriate definition (although again in the case of "K", there's this distinction with lowercase and uppercase, but there isn't for the higher multipliers... so that becomes ambiguous.)
I thus personally don't have a problem with the IEC standardization (even though I don't like the "kibi" term, but who cares, and btw, how do you spell MiB, GiB, ...? Is that MeBi, GiBi, ...?)
If there's even the slightest possibility of ambiguity, I think standardizing things is a sane idea. Just stating that "it's so obvious that it doesn't need that" is not very satisfying from an engineering POV.