And that requires more space than a typical port. In a compact device that is difficult. A flashlight is literally one of the simplest electronic devices there is and bulk is often a plus for comfort.

They can be waterproof but are also non functional until the water is fully cleared from the port.

That kind of waterproofing wears over time (years). It keeps it's resistance, but not a submersible seal. Watches have longer use years than phones on average.