Unlocking traits for defenders no use?

*AI troops will start unlocking traits as the player’s Hero levels up.

Does this mean unlocking traits for your defenders isn’t usefull?

“AI” in this case refers to the troops you face in quests and challenges, rather than teams made by players who are just controlled by AI when you fight them.

Well technically PVP opponents are AI players aswell, so might be handy to clarify that in the patch notes.