Agile in general is about predictability first and measuring a predictable velocity. Predictable velocity answers a very important question for product management which is "When can we release".
Additionally, Agile Methodology touts Cross Functional Teams where each developer is not a specialist in any one area of the product necessarily. The daily standup is a good place to indicate that a dev has run into an obstacle and seek guidance from someone else on the cross functional team who may in fact be the in house expert on that issue.
Guidance in this case typically comes in the form of "Oh, XYZ Thing, I built that - the code you're looking for is in /secret/stuff and if you look in there I think you will find what you're looking for".
What guidance is not: "Im having trouble with XYZ - will someone else on the team TOTALLY DROP THEIR SPRINT COMMITMENTS AND DO MY JOB FOR ME".
Agile and its daily standups are not about increasing velocity. They are about ensuring predictable velocity at the cost of absolute velocity (the max the team may be capable of performing at which itself will vary from sprint to sprint).
Now, all that aside, the real value of the daily standup is obviously accountability. That little 15 minute meeting forces a slacker to stand up in front of the rest of the team and clearly indicate that they either are or are not pulling their weight. Used properly it can be a very motivating practice.
Perhaps the author works in a place where every team member is a one person gang capable of independently completing any task whatsoever in the bounds of a sprint. In such an environment Agile itself does become a bottleneck. In the prefect world Agile is absolutely unnecessary - but most of us live in a world thats far from perfect.
In summary, Agile as a whole and certainly daily standups can and do act as a drag on the velocity of a proficient team. However the purpose of these practices is not to maximize velocity but rather to ensure a floor for velocity such that a team may never achieve its maximum potential but will instead continue to reliably deliver a velocity that is constant and predictable. Think of this as a sort of Productivity Insurance Policy and it makes a lot more sense.
*Additionally - I know of no law that restricts a developer from reaching out for assistance/additional guidance immediately on discovery of a blocking issue. The daily standup is just a convenient place where you have a crack at communicating with the whole team in one place. Typically with some manager type lurking quietly on the call like a parent keeping an ear on the kids playing in the other room.