Those I've used in the UK aren't so bad, they're cold fill only with a heating element in the sump. It takes maybe 15 minutes to fill and get up to temperature at the start of a shift, after that each cycle is ~2 minutes.

The hot water is recirculated during the wash, the rinse uses fresh water from the tap with the excess going out an overflow. A little sump water gets replaced every cycle, but enough stays that it's back up to temperature before you've emptied and refilled it. There's also a small peristaltic pump to top up the detergent directly from the bottle.

Not much benefit in a home setting unless you fancy having it hot and ready 24/7 though.