Answering the original question on the benefits of hybrids, I would say right now they are marginal, based on my experience with a Toyota Rav4 2016 model year.
I chose this vehicle as I needed something larger than the Jazz and the HRV I had at the time. I also benefit from 4WD, heated seats and a raised driving position, due to where I live and the back problems I suffer with. The RAV4 Hybrid was an expensive option and I managed to save many thousands by choosing a used model from Toyota's own head office fleet.
This RAV4 (there is a newer model out now with a much improved hybrid system) is a petrol electric hybrid system based on the original Prius and Lexus hybrid design. It has three motors, a 2.5 litre Atkinson Cycle petrol engine driving the front wheels, and two electric motors, one for each axle. The rear motor only kicks in when needed and it is how Toyota describe this as an All Wheel Drive car. There are three driving modes, Economy, Normal and Sport. Sport kicks in full electric power on (I think) both motors and the petrol engine too and allows you to surprise other motorists from time to time. The key difference with Economy mode is the reluctance to use the petrol engine unless you put your foot down and lower air conditioning power.
In practice this is a very easy car to drive and it returns very good economy for a vehicle of it's size and weight given a) my driving style, b) the very hilly place I live and c) the nature of a lot of my journeys. I am getting (according to the dash) around 40mpg as an average on my many short and hilly journeys around my area. On a longer run across Yorkshire I can easily approach 50mpg without using any of Jockos techniques. If I try really hard it is possible to get more than that.
The main role of the electric system is to eke the most out of the petrol engine, assisting it when it would be inefficient, replacing it in stop start traffic, boosting it on the hills and totally replacing it on the downhills whilst recharging. 'Engine braking' is available by dropping out of D and selecting a low 'gear'.
There is an EV mode but in practice, the range is under 2 miles and your speed cannot exceed something like 20mph. It is pointless selecting it as the car will choose it automatically anyway.
So the advantages for me are:
a) reduced tax and fuel consumption, having moved back to a larger car
b) a slightly increased sense of superiority and feeling that you are doing something for the planet (but not really), especially since my home town is an Air Quality Improvement Zone
c) (over a plug in hybrid or pure electric) no need for charging technology and no range anxiety
d) poor man's four wheel drive
e) it's quick in Sport mode!
f) automatic gearbox (my first)
Disadvantages:
a) batteries eat a lot of boot space and make for an inconvenient bump in the boot floor
b) not quite sure how the high voltage electrics will cope in flood water
c) more expensive to buy
d) people can't hear you in car parks and constantly stand in your way
In summary, a good idea but an intermediate technology for cars on the way to something better. I must admit, the Honda technology in the CRV and the newer Toyota technology, look like a big improvement over what is in my particular car. When I next change vehicles in a year or two it is highly likely I will have fewer dogs and can downsize again.