Everyone is different and will spend the night in different places. When we were younger, working and trying to get to our destination quickly on a limited budget, we would stop at Rest Areas. We always found that the truckers felt the Rest Areas, at least in California, were only for them. We would park at the far end, with 20 open spaces, and sure enough a truck would come in and park next to us and idle all night.
We later started finding large parking lots at retail stores that were closed and would park there.
Now that we're older and retired, we don't travel as late into the evening and prefer a campground for the night. On occasion we've been stuck and will use a Walmart parking lot.
It all depends on your budget, where you're travelling and how late you arrive. No one place is best for everyone.
I open my door for no one at night. After they're gone I do check, but not empty handed.