Board Thread:Versus Debates/@comment-26537507-20160601200935/@comment-27450558-20160612184625

Kishimoto drew sasuke activated cursed seal to broken TK and the moment he fully used Cursed seal 2 the technique was broken So this certainly has relevance.

Kishimoto didn't needed to waste two pages showing Sasuke's cursed seal if you think this isn't a important factor

There no need to show Sasuke activate the CS in reality when the battle to break the Tsukuyomi was inside the Genjutsu in a mental battle

Sasuke also used cursed seal to control Orochimaru's dimension in a mental battle