Mirage’s value to the team

I have been playing ranked with my friends and I think there's a problem with our team composition. I don't typically play caustic but I started using him in ranked because he obviously has a lot of value in playing defensively and taking buildings.

So right now we have: Pathfinder, Caustic, Mirage.

Pathfinder obviously has a lot of purpose. I don't think I need to write out his value to a team in ranked. But his scanning ability is very valuable, and his zipline is also top tier.

I believe caustic is valuable because you can place traps in a way to detect enemies, hold down buildings, etc. And his ult can shred a team holed up in a building which is really common in ranked.

Mirage, though, I feel is screwing up our team composition. I don't really feel like he has a purpose in ranked. None of his abilities really help the team and my teammate only casts his fake mirage in the direction he's already running. It's not really used to detect enemies and rarely used to run a different way to confuse enemies.

Basically Mirage is used because he can run away from fights when he thinks we'll lose and he'll hide out as long as possible to get some points that way. But I can basically hide and get points as regularly as he does with caustic, so Mirage doesn't really feel all that useful for that either.

I think if Mirage was replaced by Watson it would be significantly better for our team because we could actually hold down buildings. Other teams can set off all our traps right now with grenades and we can't hold a building with them. With watson we could 100% hold down buildings and I feel like we'd win way more games.

So do you guys agree, or am I just being a dick to my friend? Does Mirage have a purpose in ranked, or is it a selfish character?