They were for all trains using TMCC. When Mike came out with them, I put them on my layout and they are still there. I have no problems with TMCC/Legacy causing any issue with my DCS. My layout will be 36 years old in two weeks and both TMCC/Legacy and DCS play well with no issues. I have a 10 signal on every inch of track and would not settle for close counts. I do not give credit to the signal booster but do give full credit to my wiring. I worked with what I had.
I run Legacy and DCS at the same time with no issue. I am basically an MTH guy but do love those big Legacy steam locomotives. I have no TMCC left and love Legacy engines. I have about 60 of them at this time. I follow Dave and Ryan at Lionel and like what they are doing very much.