Well, if they make the dragon attackable they need to add a story arc where you kill the dragon. Sure, it's breath weapon can oneshot pretty much every PC, but only if it gets a chance to use it. Keep in mind it's a young red dragon, so no legendary resistances, no legendary actions and just a +4 to its Wis save. It would be a very hard fight, but not impossible.
So assuming that they don't want us to be able to defeat the dragon, the better solution would be to have Baretha talk to us and have the dragon fly away in the initial cutscene, so we can never interact with it in that situation.
