Question about horn circuit - 70's Dodge truck

Just wondering if anyone has any insight on this. They used a two wire hookup at the horn with no relay. One side of the horn gets power directly from the fuse panel. The other side of the horn is wired to the horn button/switch for ground - simple enough.

Why is the horn circuit (shared with BU lights) switched and not wired for full time power at the fuse panel? In other words, as it stands, the horn won't function with the key off.

Why would you want the back up lights powered with the key off? There are fuses that are always powered. Hook the horn to one of them.

Of course, I wouldn't want the backup lights to come on when the key is off - but presume that wouldn't occur unless the auto trans was in reverse - which it wouldn't be normally.

I guess I can cut and move wires at the fuse panel. It just seems an odd design, as every other vehicle I have or have owned has a horn that works with the key off.

Normal for the trucks of the era.

Thanks.