I like having options and the versatility personally 😁
The 3.5mm jack can also be used to record video audio with a much better microphone, attach a HW infrared blaster, or use your device as a crude oscilloscope im a pinch with appropriate software
The more common use case is people with existing wired headphones - there’s honestly no need to cast aside perfectly good cans for no reason. Yes USB-C DACs exist, but IMO that’s a completely manufactured expense and inconvenience, considering almost all phones still have the 3.5mm dac and amplifier components physically present on the mainboard: only now you must purchase a dongle to access the output via passthrough, or purchase a third party dongle that includes its own DAC.
My pain point though is the fact that users with wired headphones are now being forced to induce more usage cycles on a single connector port (which is not always economically repairable on modern devices), and all the avoidable e-waste produced by these things when the unreplaceable, consumable batteries give up the ghost after two years of ownership