If I were to guess, maybe the OP thinks it’s more “aero dynamic” to have a plate conformed to the bumper than a flat plate. That would be the only reason I might do it.
That said, I wouldn’t do it, it looks like someone smashed into the bumper, crushing the plate onto it.
I just got my plates today, but haven’t installed it yet since I was on my way to work when I noticed it. I bought a license plate bracket from Amazon, that attaches to the grille. I’ll make use of it once I get home. Not that there’s any rush, since the temp won’t expire till end of May.
Supposedly, Illinois has a proposal to eliminate the need to use front plates, so I’m hoping it passes and takes effect soon.