A colorspace conversion is taking place ... sRGB isn’t going directly to the printer, somewhere there is a conversion to the native output color space. The de facto printed gamut will most likely deviate from sRGB (and all one has to do is build a profile from the process and plot that gamut to see this).
conversion. The Fuji printer ignores embedded profiles.
The RGB data supplied are simply converted to print "as they are".
What we are talking about here is a wrong or less wrong Assign / gamut assumption
as opposed to Convert. Trust you know the difference.
If the RGB data supplied are in ProPhoto RGB, it is simply a totally wrong assumption about the print gamut. The print will be hosed. If the RGB data are in sRGB, it is a somewhat less wrong assumption. Good enough for Many. And if the RGB data were derived by proper conversion into the printer profile, it should be an accurate, CM correct approach – depending on the quality of the printer profile though.
Let’s focus on mechanisms instead of semantics.