Difference in downforce is another significant difference. The downforce generated by an F1 car is equal to the car weight at around 100mph and almost 2.5 times the car weight at full speed. The downforce in a NASCAR is far less for a much heavier car. Though F1 may not have traction control anymore, they still have a lot of electronics to assist the driver, where in NASCAR everything is up to the driver. F1 uses flappy paddle gearboxes that are computer controlled, except for 1st gear. Not NASCAR, work that clutch and gearshift. In other words, everything is manual.
What is interesting and what is not depends on the preference of the individual. Personally, I find almost all forms of auto racing interesting. NASCAR has side by side racing, F1 has breakneck speed around circuits, ALMS has multiple classes on one track etc etc etc. Each offers something that the other cannot.