In response to the OP, we've had experience of driving a plug-in hybrid for two years. And I’m a sad person who has recorded on a spreadsheet all the fuel I’ve bought for our cars over 20 years.
Mrs H leased a plug in hybrid, a BMW330e. The car covered less than 12,000 miles in two years. Much of Mrs H’s driving involved short trips of around 10 miles in a day.
On shopping trips the car was quiet and docile. However, on a longer drive, seamless power was delivered whenever required! The car was a joy to drive. My wife achieved amazing economy whilst I had the fun of huge torque delivered incredibly quietly. Totally trouble-free for two years the car only visited a dealer once, its first service after 24 months.
Electric drive is incredibly relaxing and smooth. Obviously one had to be careful to drive slowly near pedestrians as the car was very quiet in a car park situation. On a full charge, the car would go for around 14 miles on electric power only, provided the speed was below 65mph. (On a 2020 model this range has been doubled, I believe).
There was never any range anxiety, as the car had a range of substantially more than 400 miles on a long trip.
Over 11,292 miles the car used 726.05 litres of petrol. So it achieved 71 mpg.
The car was charged most evenings and I estimate that over two years it consumed around £240 of electricity.
If one notionally converts the £240 into litres of petrol, at say an average of £1.20 per litre that would be the equivalent of using an additional 200 litres of fuel. This gives a notional total consumption of 926.05 litres and an overall notional fuel consumption of 55.5 mpg.
So, not bad for a powerful car used mainly for short runs.
For comparison, the Merc C Class diesel which preceded the hybrid got 44 mpg over 26,000 miles and the current replacement is a petrol VW Golf 1.5 TSI which is getting 43 mpg under similar driving conditions.
More details are on viewtopic.php?p=144638#p144638
More recently I read a report by Which magazine which investigated why Toyota cars were incredibly reliable compared with virtually every other car make (and far more reliable than fully electric cars!) They have asked their thousands of subscribers about their cars every year for around 30 years and have a very high response, so probably know more about car reliability than the rest of us. Which’s conclusion, after quizzing Toyota, was that most Toyota's are hybrids and this design means that the petrol engines are simpler and less stressed because the electric motor takes the strain of starting off at low speeds.
Hope this is helpful.