If this works for you it's awesome, congrats. But what I saw in the past (3 different companies) was more like 30m+ standups, because most people (funny enough especially project managers) tend to talk way too much during standups. Unfortunately.
There's your problem. That role is the antithesis of a self organising team. With someone responsible for "managing" that stand up turns into a very expensive way to keep the manager briefed.
A good team will often find ways to achieve these things without requiring the Scrum Master to step in.
*edit: missed a word