To make those 2 commands available, users have to enable a specific setting in customer defaults, Similarity Engine (found under Gateway > General > Selection tab, ootb this option is disabled)
Once enabled and rebooted NX these command will be available to users, either in the ribbon or the menu.
No license prerequisite is clearly mentioned in the What's New Guide, but for any customer without the proper license even the customer defaults option won't be available at all.
Solution
Actually a specific license is needed to enable these 2 new commands. Without the license feature named 'nx_ml_show_hide' as stated above even the 'Similarity Engine' option won't be available within the customer defaults. The new license feature is available with these commercial NX bundles:
Any NX bundle will be ok to get this last add-on. Likewise this license feature is available in the NXACAD100 (NX Academic - Core & CAD) bundle and UGDIST100 (NX Distributor) license code.
Hardware/Software Configuration
Platform: all OS: n/a OS Version: n/a Product: NX Application: SYSENG Version: V1953 Function: SELECTION