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You'd normally do that, yes, but it's not strictly required in all applications. The speaker itself might already act as a low-pass filter simply because it can't physically react fast enough for the high-frequency part.

This would be required for a true DAC, but not here:

- A physical speaker already acts as a filter due to inertia

- The PWM frequency and its square harmonics sit far beyond the human hearing range

Well then you wouldn't be playing audio without a DAC, would you?

How would you consider an RC filter a DAC? there is nothing digital about it

It's a reconstruction filter, the simplest DAC you could build.

Most of the digital parts of DAC chips are not there for conversion, but getting data ready for conversion through a reconstruction filter. You don't need that if you're driving a PWM signal through a cap to integrate it.