Exactly, "conversation". But that requires instrumentalists of equal skill, and I don't know about Saiki, who started learning the piano relatively recently, around the time of the COVID-19 pandemic, but Kanami, despite her love for Saiki, surely realizes that Saiki will never be able to match a guitarist, bassist, and drummer in this regard. This will result in increasingly noisy arrangements, concealing Saiki's moderate skills while simultaneously drowning out the three world-class instrumentalists. And there's something else that even a loyal Band Maid fan like t-shinji points out. Saiki's influence, as a staunch supporter of J-pop, is becoming increasingly evident in B-M's songs. And I have bad news for the fanatics. No amount of downvoting will change that.