I'm betting that these are effectively dedicated hardware controllers for the 4 voice System-1 plugout code that lies within.
And that each contains a software emulation of their parent (JX/JU/JP).
You can poly chain them for 8 voices, and at these prices, why not?
Batteries, sequencers, patch memories, mini keys are OPTIONAL (Bonus!)
Looking at how good the Roland plug-outs sound (SH-2, SH-101), if these are as good, they'll move many.