Ann: Q2FY19 Activities Update and Appendix 4C, page-87

Physics/characteristics of the respective memories will determine their applications.  

WBT = filamentary (requires error correction, impacting speed).  4DS = non-filamentary, that means interface switching and no error correction required.

Existing filamentary ReRAM companies (e.g. Crossbar, Adesto) are all producing embedded memory.  WBT's recent announcements and presentations make it clear that it is also targeting embedded memory (low volume, low density).  This fact is even reflected in the revised terms of wbt's IP licence agreement with Rice.  

In contrast, 4ds is seeking to make stand-alone storage class memory (high volume, high density).