Not going to do that with groceries, and generally it takes too much time and effort (this city is built on a lot of hills) and is too dangerous around here. Nicer bikes get stolen a lot (I lost 3 before I lost my patience and didn't buy another one), cars are much harder to steal.
I live in a city that's often said to have the best public transit infrastructure in Europe and one of the best in the world.
I still use my car to go shopping and to transport myself. Carrying bags of groceries from the shop to the station, and from the station to my house is a lot of work and I'm not going to do that in bad weather.
And public transit is much slower than going by car. For example: My doctor (that I have to visit every 2 weeks) is 25 minutes away by car and 1.5h by public transit.
Don't trust stories about how you can work or read in public transit. The vehicles are so full in peak times that you're happy you at least get to fit into the vehicle.
And it's a thoroughly bad experience during summer, I am sensitive to smells and I just can't do it, the body odors are too much and I'd throw up immediately.