Interesting that the airbags didn't deploy, suggests it wasn't a particularly hard impact.
Well, low speed. I wouldn't have guessed that damage would write the car off.
Cars with better NCAP rating have the best front and rear 'crumple zones' which absorb energy by deforming to stop energy of impacts being transferred to occupants, which is why big 4 wheel drives with their solid chassis used to be actually more dangerous for occupants than passenger cars, the chassis stayed solid and all the energy of the crash was transferred to the occupants, (think of shaking a stone around in a can LOL). The Jazz with its centrally mounted fuel tank (the safest place for it) can actually have better rear crumple zone than a lot of other cars. The side doors of the car have strong sections of metal beams across them about halfway up the door to stop doors being pushed in by side impacts and to help keep door in shape so that they can still open.
I remember a few years ago on top gear when they did a frontal impact of a newish Renault Modus against a big solid Volvo estate of about 10 years old at the time of test and asked viewers to guess which driver would come off best in a crash, I bet I wasn't alone in choosing Volvo but turned out Volvo driver came off worse and front doors couldn't be opened and according to damage to the poor old crash test dummy the Volvo driver would have been killed / seriously injured but Renault driver was fine even though damage to Renault looked worse because its front had collapsed a lot more than the Volvo.