Having owned a number of houses - the biggest reason is peace. I've owned houses where I felt the neighbors looked in your back window, everyone could hear what others are doing in their yard around you...
Walking out and having a bit of space is wonderful. And tools like slack and hangouts are making it easier to work remotely as well.
Oh, there's a lot of things you can do with 4 acres. You can maintain extensive gardens and supply substantial quantities of your own food, as a profitable hobby. You can consider owning small farm animals like chickens, or maintain apiaries. Children and pet cats/dogs can run around outside and the children can exercise their imagination through unstructured play in a safe environment, especially in a multi-child family, potentially replacing overly-structured and expensive after-school activities for all but the youngest children (with many opportunities to increase their physical fitness through such activity). You or your children can also practice sports, such as baseball.
I lived in a tiny apartment right in the city growing up. And I mean very, very tiny - we shared beds. I did all those things in my city-dwelling childhood. You don't have to own the land to do that stuff. In fact city life lead me to spend plenty of time with the neighborhood kids, which was really great and you don't get that if you are spending all your time on your own property. If I was bored I literally just walked outside and see which of the neighborhood kids were out. I don't believe there was or is anything "unsafe" about public property and you can do sooooooo much more on public property. We did have a very small backyard that was shared with 6 families and we spent plenty of time there. And we got to interact with the other kids who lived in the building and the kid next door who saw us playing. You can also find a surprisingly large amount of nature in the city if you go looking for it. The idea you need to own 4 acres of land to play baseball is just laughable.
I'm fact, seems more like living on 4 acres would be a prison. You couldn't leave without being driven!!!
The problem is kids aren't allowed to go outside anymore by themselves.
Growing up with very little made me such a better person. I'm way off the hedonistic treadmill.
I wouldn't call it public, it's more of a shared space an apartment complex might have.
The larger the city, the higher is the likelihood of public spaces having a variety of homeless encampments, broken glass, needles and plain old feces.
The larger the city, the higher is the likelihood of accessible but nevertheless private property having those same things; though in either case its likely to be restricted to particular parts of the city, and those are likely to be the ones with lower property values (this reduced property value is both a cause and effect of the condition, its a positive feedback loop.)
The larger the city, also the more likely public -- and accessible private -- spaces are to be fairly pristine enclaves. These will usually be found in substantially different parts of the city than the nasty bits.
Besides they yard was an after thought, I spent most of my outdoor time in public places and I was outdoors every day in the summer.
You may just as well say "I'm too good for public property, I'd rather not share with the peons." Don't hide behind "safety." There's no major safety issues in letting your children use a public park.
And anyways, it's probably much safer to let your kids have a hypothetical chance of running into hypothetical broken glass (that they can just walk away from) than to put them in a car every time they need to go somewhere, as automobile accidents are the leading cause of death in people ages 5-25 (or something along those numbers)
And bicycles are great kid transportation...