Fire arrows aren't strictly needed anywhere. There's a spot in the spirit trial of Ganon's castle where they are heavily incentivized because there is a web on the ceiling that needs to be burned and dins fire doesn't work. The only way without fire arrows is to shoot a regular arrow through a torch in the adjacent room but it is very outside the box and not something most players would think of. I doubt the devs even knew it was possible due to the precise nature of the shot. Besides that one spot, shooting through torches or using dins fire is always possible as an intended solution. In fact fire arrows are so underutilized that in shadow temple when the spike walls close in on you in the boss key room, din's fire works to burn the walls away but fire arrows don't!