I was going to post exactly the same thing myself. Most front doors these days have multi point locking systems and are very difficult to break down unless you are using a sledge hammer or angle grinder etc.
But you negate this super strong front door if you decide to unlock it from the inside.
Like you Paul, I never open my front door after dark/9pm.
I had a guy knocking on my front door one dark night last winter.
He had a pizza to deliver, but I hadn't ordered it.
Even though I told him I hadn't ordered it and that I wasn't going to open the front door, he insisted that I take delivery.
Eventually I told him to fuck off, and he decided to take my advice and went.
All done while shouting at him through the living room window.