In addition, Akkadian used cuneiform not only for phonemic writing, but also had many signs borrowed as-is from Sumerian as logograms (sumerograms), e.g. for the words for sheep and king. So in that sense it is indeed very similar to Japanese.
Egyptian did that too (and that writing system developed independently as far as we know) -- it's interesting that multiple ancient cultures did that (and as you mention modern Japanese isn't that different)
