From past experience, those claiming that TCAS/TAS is detrimental equipment which merely "drives the pilot's head inside the cockpit" are likely to be those who haven't flown with it on a regular basis. Used correctly, it naturally becomes part of an effective lookout scan. A brief glance inside is all that's needed, as the pilot looks from left to right during his lookout scan process. The shortcomings of the system are well known and due allowance has to be taken, but seeing a transponding "blip" at a range of up to 12 miles allows the user to take far more timely avoidance than relying on the much shorter range of even the best human eyesight alone.
The reason some pilots say "Got him on TCAS" is probably to reassure the ATC controller so he can perhaps concentrate his attention on another developing situation and make the necessary RT calls to other aircraft, at least for a while. So don't criticise, the pilot is actually trying to ease the controller's workload in order to help others!
Having flown a number of different TCAS/TAS equipped helicopters over the past twenty years, (and twenty more before that without it, military fixed wing and rotary plus some civilian stuff) I would now feel very vulnerable without it. It's shown me many times that most pilots don't look out effectively, or don't know the rules of the air. Seeing as we all take the air law exam, (and hopefully no-one actually wants to be involved in a mid-air) it's more likely to be the latter!