Perfect for an non-handicapped person responsible only for themselves!
And who lives in the city not far from the public transit.
I'm not sure if you were being sarcastic but this only works in specific cities. Lots of cities have issues with sprawl, weather, lack of bike lanes, or even a place to lock your bike. It's also extremely difficult to do with a young family.
Only in warm climates.
Also good luck carrying your children on your bike.