He did answer though. Seasonal mechanics and items first and foremost belong in their season. When the season ends, the seasonal stuff is gone, and something new awaits in the next season. That is how it works. IF a seasonal mechanic or item is popular enough, and not disruptive to future seasonal themes, it may become a permanent addition, but in the case of chaos armor, its just very unlikely, as it would make it next to impossible to create any future seasons revolving armor pieces. This is the same reason the jewlery gems from past seasons never made it to eternal, there is only 3 jewlery gem slots, just like there is only 5 armor slots. If you lock these in with a previous season mechanic, you cant create a new seasonal mechanic for them in the future.
So to answer your question. What is the point of collecting chaos armor? So you can use it in the current season.
Seasons are not a means to an end, to feed your eternal characters. Seasons are the main game mode, not eternal.