Yes, like all systems, it has tradeoffs. Although I would argue that some of the downsides you highlight are worse with traditional bus systems (e.g. the Caribbean bus conductors will happily guide tourists, and I have seen them go off-route frequently to drop off someone with limited mobility. Large cities in other parts of the world have managed to scale the system out to fill in gaps with other forms of transit like Lima, Peru)

The GP was arguing that it NEVER works out, and I'm just pointing out that it does work in many places.

I would much rather rely on the Caribbean minibus systems than try to rely on transit in cities like Phoenix.

> They make it difficult for travelers to predict journey times

How do scheduled bus routes standardize a journey time vs a demand shuttle?

> out of the way journeys in my experience.

How do buses fair in this regard?

> It's really not ideal

Are buses?

To standardize a journey time in a scheduled system, you subtract the origin scheduled arrival from the destination scheduled arrival. Map apps will even do this for you automatically. If the bus is unreliable, you add error margin. A demand shuttle system usually has a much larger variance, which means you can't predict that the journey time will be acceptable and you'll find some other way to get around.

    How do buses fair in this regard?

You look at the route map and the schedule to decide? Again, map apps make this trivial for regularly scheduled services.