Some US washers don't but many do. However, US washers tend to not heat water as quickly or to as high of a temp. The video cites two reasons: 1. US power being 110V vs 220v. 2. US dishwasher heating elements being limited to 800 or 1000 watts because many are designed to potentially share one 20A residential circuit with an oven and/or fridge due to possibly being retrofitted into a kitchen built before built-in dishwashers were standard and manufacturers not wanting to create different models for retrofit vs new installs.

American dishwashers are typically hooked up to hot water. Some will have heaters but they're not that powerful and they may only run for the main wash cycle

I can’t speak to Australian dishwashers, but trying to skip the video by catching a summary has failed you. Heating is discussed extensively in the video

American dishwashers don't have their own heater?

Some do, some don't.

The ones that do vary in ability by overall dishwasher quality.

The ones that don't are hooked up to the kitchen's hot water line.

This is considered more energy efficient because a home's hot water heater (whether electric, gas, or another fuel) is better at heating the water in a bulk capacity than a tiny heater in the dishwasher.

The downside is that the cold water between the big water heater and the dishwasher has to be purged first for it to be really effective. If your hot water heater is in the other side of the wall, no problem. If it's six rooms away, problem.

A dishwasher cycle is usually only going to run for a specific period of time. Its more effective it if starts that time closer to the proper temperature rather than relying on waiting for the heater to get the temperature up to that time. Especially on the pre-rinse cycle, where the heater may or (probably) many not engage.

Same in NZ, never seen a dishwasher with a hot water connection.

They do. I didn't realize this until my natural gas supply company decided to replace my meter on a Friday. Without alerting me ahead of time so that I could, you know, plan to be gone while my house had no hot water.

Whenever natural gas supply is turned off in the US, for any reason, only the gas company can turn it back on. And they can't do so if there's a leak at all. You have to call a plumber to come out, detect the leaks, and fix them. After that, you can call the gas company to come back out (but not on a weekend) to turn it back on. And a same-day request for service requires someone to be home ALL DAY after it's called in.

And this is how I ended up showering at work for three days that week after not having had one over the weekend.

This has always struck me as dumb, as until recently it was far cheaper to use your existing (gas-fired) hot water than to use a resistive element. However, with gas going out of fashion (and already hugely expensive in the Eastern states), and abundant solar PV, the calculus has changed.

They do, but they are generally confined to 10 amps, so they do not heat quickly.

My fairly cheap dishwasher in the UK has its own heater, but you can attach it to a hot water supply, which may save money as gas is so much cheaper than electricity.

traditionally (in household washing machine time) US houses were large and had a lot more hot water capacity for the whole house, and putting a heater into individual appliances was not necessary/cost effective.

retrofitting old traditional houses (especially stone) with higher capacity plumbing was expensive and infeasible, so putting heaters in appliances was a cope for markets that needed it.

Quite, another thing to add to the list of USAian weird exceptions.