I feel like the UPS person will leave my package on top of this
I can absolutely confirm that they will :-(
I have a beautiful parcel box installed outside my house and I'd say that maybe one in twenty deliveries uses it. It feels like the only thing it achieves is to allow me to proceed through dispute resolution a little faster by pointing out that "it was YOUR delivery person who refused to follow instructions, so give me my damn refund".
Maybe in five years parcel boxes will become common enough that delivery personnel use them. But as of today, in a large metro area, they are mostly by every carrier, in spite of specific delivery instructions that have been registered with every carrier.
EDIT:
based on reading more comments.
My particular parcel box doesn't need a PIN or any other fancy details. It is somewhat like a mail box (though the mechanical details differ) so that you can open the top and drop something IN, but you can't take something out, there are metal sheets that block your hand going down.
So even though putting a parcel in is literally lifting a plastic lid and dropping the box in, an extra 3 seconds!, delivery people don't do it.
There seems a lack of interest in doing the job properly that's a barrier you just can't get past.