Unfortunately, many engineers will consider themselves “blocked” after doing only 5 minutes of research and deciding they needed to interrupt someone else’s work for help. They are concerned only with their own productivity, not with the productivity of other team members who have to context switch to solve a different problem.
A standup encourages people to solve their own problems as best as they can, and to aggregate their interruptions to limit the number of individual interruptions throughout the day. Without a system like this, a team’s senior engineers may get nothing done besides assisting others.
Which make standups useless. If I have blockers I communicate them right away. I don't wait until the next standup to do so.