I’ve got a Prius, an older one.
There’s no clutch, and no torque converter or anything similar. Varying the wheel torque and speed is all done with electric current. So provided you have traction on the tyres, it’ll be fine.
The transmission has a huge range of effective gears – it can change down to an almost infinitely low gear, so when going up something really steep the engine note keeps climbing so it feels like a slipping clutch, but in reality you’re continually shifting down. It has to be silly 1:3 steep to notice this mind.
Turns out it is no better than my standard diesel, which drives far better and is much quicker…
Mine easily does 60mpg on the motorway in summertime, which is about what I’d expect from a ‘standard’ diesel like my other car. However it also does 55mpg round town, where my diesel can drop to 38mpg. The new Priuses are better and faster. So they are better, just not spectacular. Cleaner at the tailpipe though.