Why Do We Need Priests?

I know that this is an odd question, but if I am challenged with this question, I don't really have much scriptural basis to support it.

A common rebuttal from Protestants is "if Christ is our mediator/high priest, then why do we need priests in a church?"

Here are some of my reasons:
- Priests and high priests have different roles

- Because of Apostolic succession, priests are considered icons of Christ

- Structured spiritual guidance and fountains of knowledge

- Forgiveness of sins (in 2 Chronicles 19:10, Jehoshaphat offered penance)

Are there any more reasons to add? Also are any of these reasons invalid?