It was appropriate for God, for whom and through whom everything exists, to use experiences of suffering to make perfect the pioneer of salvation. This salvation belongs to many sons and daughters whom he's leading to glory.
This is because the one who makes people holy and the people who are being made holy all come from one source. That is why Jesus isn't ashamed to call them brothers and sisters when he says,
12I will publicly announce your name to my brothers and sisters. I will praise you in the middle of the assembly.a13
He also says, I will rely on him.b And also, Here I am with the children whom God has given to me.c14
Therefore, since the children share in flesh and blood, he also shared the same things in the same way. He did this to destroy the one who holds the power over death—the devil—by dying.
He set free those who were held in slavery their entire lives by their fear of death.
Of course, he isn't trying to help angels, but rather he's helping Abraham's descendants.
Therefore, he had to be made like his brothers and sisters in every way. This was so that he could become a merciful and faithful high priest in things relating to God, in order to wipe away the sins of the people.
He's able to help those who are being tempted, since he himself experienced suffering when he was tempted.