The death of Duncan takes place offstage in Macbeth. Why might Shakespeare have decided against showing Macbeth commit the murder?

I think that there are two ideas at play here. One is that the off stage murder builds suspense. We already know that Macbeth is stressing himself out over the potential murder through seeing the dagger in the air. The audience wonders if he can actually do it. Also, it was quite taboo to show a king dying on stage during the time the play was performed.