Keeping your car parked indoors overnight keeps it warmer in the winter, cooler in the summer, free of bird poo and water spots from rain and dew, eliminates scraping windows and sweeping off snow in winter, protects against sun damage, eliminates warm up time in winter, protects against them getting hit on the street, adds another layer of theft protection, etc. Lot's of benefits, particularly in cooler climates.
Pull the cars out and you've got yourself a great workshop to do projects, a place to play ping pong, set up the chairs and tables for a cook out, play music, etc.
I probably spend more awake time in my garage than I do the house.
Also with proper shelves and storage set up you can store all of your tools, bikes, toys, etc. out of the weather.