Samsung Debuts 128 GB and 256 GB Variants of Galaxy S9 and S9+
Otherwise the 64 GB standard version suffices well.
Micro SD cards can hold the extra baggage of movable apps to SD and photos as well.
Having so many files and apps on internal storage creates mounds of redundant files which weigh down phone performance.
External memory capacity of 400 GB well takes care of 128 GB and 256 GB variants.
Samsung learned from not having external memory on the S6 and the S6+