It's been a long time since I worked in flight simulation (full flight simulators and simpler pilot training devices, including simulating TCAS), but I believe at that time TCAS would be switched to a mode in which it only alerts of "Traffic" instead of providing avoidance instructions precisely _when_ entering busier airspace -- e.g. airport proximity. In that environment it was undesirable for TCAS to be giving instructions. That seems like the environment in which Enhanced Radar's (future) product(s) could be of most interest.
(By the way, I believe EGPWS would take priority over TCAS anyway.)
(By the way, I believe EGPWS would take priority over TCAS anyway.)