I had similar thoughts. I live on the west coast and feel so safe that I don't even lock the front door to my house, ever. I wonder if OP feels safe enough to always have their front door unlocked.
I wonder how much people think the typical flimsy locks on a residential door will actual stop someone who goes up to the door with the intention of entering. It would almost require someone to want to enter but iff the door was unlocked, which seems like a poor strategy for a burglar.
It's only a poor strategy in places where people lock their doors all the time.
If people lock their doors all the time, burglars probably prefer to avoid the houses with unlocked doors (because they are more likely to be occupied houses).
Locks won't stop somebody who wants to get inside no matter what. They will stop somebody who would not mind casing the house, waiting till it's empty, entering without attracting any attention and walking out with loot, which is a "safer" crime than knocking down the door or breaking a window. Breaking and entering is a crime by itself, carries minimum sentence in some jurisdictions. As I understand it's because it's hard to convict somebody who walked in, took stuff and sold it for anything other than trespassing. How do you prove they stole the missing items unless you catch them in the act or have video surveillance inside?