It's an emotional note, something that can't be qualified.
First, as far as storytelling goes, it reminds us, without simply a cheating reveal at the end, of the contrast between the timelines. The story on the bridge is minutes long, while' Kamin's is decades. This is not just told to us at the end of the episode... it's shown to us by how much progress Riker and the crew have made. I believe it's the end of the first act that Riker finally says "Sickbay, the captain's hurt.' If the narrative had stayed with Picard for the whole episode, and then at the end Riker says "oh, you've only been out for a half hour" the audience would be like "Oh really, you could have fooled me.' but this way, we are shown both timelines at their relative pace. Plus, the crew story line is the one we usually follow every week, what the crew does, so using it hear interspersed with the Kamin stuff serves as out familiar touchstone, and the writers were smart to have it gradually become less predominant in the narrative.
Taking it away entirely, however, would have left us asking 'What's the crew doing?' instead of thinking 'Wow, he's living many years in thirty minutes' which is what we should be thinking to ourselves. Indeed, revealing this a bit early helps with our sense of wonderment. We know a bit more than Picard, so when his epiphany comes, we see him react to it, we are crying because we wish we could have told him decades ago.
From Jammer's review:
It's an intelligent story telling technique. Sure, a case can be made to keep it all in Kamin's point of view. But the writers have forty minutes to tell a story, and this is what they chose, and they gave us a few touchstones for setting up it's pace., Otherwise we'd be asking the wrong questions throughout the episode like "where's the crew" and "what's happening on the ship" rather than thinking about the deeper issues.
I honestly don't think anybody would be asking "Where's the crew," given the strength of the Kamin storyline. Let's remember that many of the complaints in this thread are more about "Forget the crew! Give me more Kamin." If that's the case, then few are asking where's the crew. And the point about the familiarity further removes the uniqueness of the episode precisely because Picard's doing the actual exploration here, while the crew struggles to maintain the status quo -- which by default doesn't have a lot of dramatic tension to it. If Picard is our concern, let's stick to focusing on Picard, and not something manufactured because traditional plot structuring calls for it. The story is pretty unique for Trek, and therein lies one of its better strengths. Go with it, run with it.
Thus, it's simultaneously a praise and a criticism of the episode -- the writing for Plot A was so engrossing that Plot B became unnecessary. If anything, reducing Plot B to just the bookends not only maintains the temporal comparison to both sides of the story ("Riker, you're teling me I've been out for 20 minutes? But I lived several decades in a 40 minute show!" That comparison only needs Riker in the end, not every 10 minutes or so), but it also gives the writers more time to work on Kamin, which would build upon an established strength. The viewer is already thinking for themselves while watching Kamin's story unfold (as the main concern is watching Picard evolve on a personal level), and the viewer never forgets that they are, after all, watching Star Trek, so there's no need to hammer in the crew. So you want to keep the fate of the planet on the viewer's minds? State that near the opening, before Picard gets shot and turns into Kamin. Just as the viewer doesn't forget that they're watching Star Trek, they won't forget that very important plot point. Have the crew determine it early on so that they don't interrupt the Kamin storyline later in the episode.
To wit, other Trek episodes have centered on few characters with the main casts relegated to just bookends (if even that!), and in very few of the cases, the viewer asks where they are. Oftentimes it makes, say, a rescue all the more dramatic. In this case, the writers would have time to actually use drama as study -- life is hard and wondrous, after all. Life is worth exploring, and life makes an impact.
As for pace, as mentioned earlier, I thought the pace was just fine, up until it came time for the message to end. Removing the bridge scenes could help streamline the pacing at the end. I feel like 95% of the episode was finely crafted but once the writers realized they had time constraints, they had essentially pull up the curtain game show-style on Picard.
I believe had this episode been made later, the writers probably would have taken more risks or reduced the crew to book ends. TOS and TNG had their tried and true plot structures, but the later spinoffs would take more gambles for dramatic purposes. Additionally, we probably would have gotten more of a conscious follow-up, too -- Kamin deeply affected Picard, as the episode keenly shows us in the end with the flute. But this episode only gets referenced twice, once perhaps accidentally. If Picard behaved differently from that point of the series on -- perhaps less rigid yet even wiser -- then there'd be a bit more consistency.