So is there a point to this ending???? (

Remember in the original Star Wars when they said "this information came at a great price"? This was the great price.

I disagree with your assessment. Yes, they completed their mission and yes it was a dangerous mission, that they might not return from, and didn't. Why do you insist on getting a happy ending every time? How do you not see the Virtue and Nobility in dying for the cause? You've seen STAR WARS right? They saved WORLDS from that weapon! There is no grey area here, They done good. Consequentially Good. They knew the risk, they paid with their ( Imaginary) lives. Why do you want to always have a happy ending?
That's not good story telling, and I hate to break it to you, but, life is going to break your heart.

I don't see the heavy "comic tone".
What I see is a Star Wars film with greater shades of grey. Characters who have committed terrorist acts beyond the pale of the moral tone of Star Wars. AND it still fits in perfectly because these dark rebels sacrifice themselves for the cause. Their deaths, including all those that were essentially innocent, purify the rebellion.
I believe that is the point...

Maybe they wanted to show us the other side of what we had seen before.

Is there a point to this movie???That’s the more appropriate question.

I think they got the ending right, every single fan in the audience remembered that those plans were acquired at a terrible cost when the final scenes rolled. I don't think it was absolutely necessary for the fandom to know what that cost actually was, but since "R1" is so good, I'm willing to grant this film an honored place in the canon.

It's a dark film overall, even though it has a few laughs here and there; it's a movie about desperate characters living compromised lives, and getting personal redemption instead of a happy ending, because there are no happy endings for some people. Plus, there had to be a reason that Jyn and Cassian weren't the coolest kids at the Rebel base when Luke arrived.

The ending and deaths of all of the key characters lends weight to that scene in Return of the Jedi when they are referred to by (forget the character's name) and the council meeting of the rebel alliance right before they plan their attack on the new Death Star. I remember back then when she said many Bothan spies died retrieving this information and how destitute she looked when remembering their sacrifice. This movie in the very least pays homage to the theme of sacrifice.

IMO the best thing about the film is the ending they won but the cost was their lives. Yes the hero doesn't always survive look at the Skywalkers they all died for Palpatines grand daughter to steal their legacy...life is not always fair !