It's nicer to add plugs to lamp posts. If you can retrofit existing posts, there's less electrical/digging work involved. If not, you are adding lighting at the same time. E.g. https://ubitricity.com/en/charging-solutions/ac-lamppost/
Lamps use a specific voltage and amperage useful for lighting, not charging cars. You’d have to completely overhaul electricity to lamps, while also having a transformer for the lights, and at that point you might as well do something purpose built. Lamps are also not built next to each spot you’d park a car.
You can slow charge with very little amps (eg 5A/1.3kWh). Some charge is better than no charge and it’s not too much of an issue if you are street parking for an entire day or night.