It's not about ending, but the branching story isn't actually branching at all. You make a decision and, regardless of what you chose, end up in the same place. The amount of decisions that actually stick, or actually change your progression through the game, are very low. "Do x or y" where both X and Y cannot be undone and seem like heavy decisions, ultimately do not change the outcome of any future story items. Side with Ben or side with Jill, doesn't matter, they both treat you the same afterwards and it never mattered at all which you picked.

Even with just one ending, a game can do branching well for all the sub-story endings that most games have.

Hell, even The Witcher 3 did this incredibly well. Spoiler incoming for those who haven't played it yet.

"The Bloody Baron" quest not only has three endings, IIRC, but one of your choices can lead to entire village dying. And I'm pretty sure there's a few other variables that can end up having some effect at later points in the story.

Granted, it's probably the most-cited example of great Witcher 3 quests, second perhaps only to the romancing options (again, 3 possible outcomes), but I've already come across a few more main and sub-quests where reloading and trying a different option was meaningful.

As part of the journey, they might not affect the ending, but in an RPG style game with quests, it's just as much about the journey.

Not comparable, your choices actually "matter" as you play the game, until the end where it's revealed nothing you did mattered.

In this game the lack of choices mattering is apparent from the beginning. Most gamers may not care but for a certain type of gamer, this is a game ruiner.

For example with ME3 again, I had fun the entire way through the game, assuming my prior games' choices mattered. And there actually were different dialogue options, references to past choices, etc.

The ending was awful, and I will never replay that game ever. But if my choices didn't matter even while playing, before the ending... well that's just an awful game to a person like me. I would never play a minute of a story-based, choice-based game where I know the choices don't matter.