Isn't GiB = 10^9, GB = 1024^3? Some people seem to use them interchangeably.
k/M/G/... come from SI which is based on 10^3. Ki/Mi/Gi/... are for 1024.
I believe the virtuous answer is that bytes are measured in powers of two, & hard drive manufacturers are dishonest. (Bits are measured in powers of ten)
You'd have to add ISPs to that too, as network links are typically measured in decimal increments.