I fail to see how TCAS can be very useful in a military aircraft in terms of safety.
In controlled airspace the risk of collision is already very low and TCAS RA could be selected without any real problems, but it is a solution without a problem in controlled airspace.
In the open FIR, jets cause all kinds of problems for current TCAS equipped aircraft with RA selected, so I fail to see how fitting it to jets would help.
If left in TA mode it can be quite useful at times, but as anyone who has used it knows it is very rough and ready as a kind of map view. Not convinced the time spent looking at it wouldn't be best spent looking out.
I found it most useful for spotting reaper/pred in their orbits at medium level. Tricky things to spot visually, but I would mention that they can take a long while to find. longer than you would have steaming through at speed.