Yes, but 1 kB = 1000 B. In this case a difference can be made by the lowercase or uppercase "k". However, with Megabyte (MB) this is not possible, because the SI symbol is already uppercase. So to indicate the difference, the unit "Mebibyte" with the symbol "MiB" was defined.
I would prefer to use Megabytes, because they are easier to imagine and to calculate with. E.g. if I upload 15 files with 100 MB each, then the total amount of data is 1500 MB which is exactly 1.5 GB. However, if I upload 15 files with 100 MiB = 104.8576 MB each, then the total amount is 1500 MiB, but that's not 1.5 GiB, but 15 * 104.8576 MB = 1572.864 MB = 1.57 GB = 1.46 GiB.
The best would be if there would be an option to switch between SI and IEC prefixes, because some file hosters use calculations based on 1024, although they use SI prefixes, e.g. MegaUpload.