I’ll have a late stab at the original question, based on some slightly hazy music lesson memory

The rests (and notes for that matter) generally get written on the usual divisions of a bar but not crossing one unless it fills both sides.* In the end this might use more ink, but results in notation that’s easier to scan and sight read while keeping time. It’s a bit like putting spaces between each word in writing.
So in 4-4 there’s 4 beats, 1 being “strongest”, 3 next strongest and 2 and 4 being the “off beats”. If I’m counting along it might be ONE two Three four.
The crotchets occupy their beat, so that’s fine.
A minim at the start or end occupy 1 and 2 or 3 and 4, but don’t cut across the 3 beat. So they’re fine.
A minim in the middle would cut across the three beat, so is usually written separately. A long note might be written tied in that situation.
A four beat rest occupies the whole of the bar, so it’s ok that it cuts across the three beat.
In other time signatures those logical divisions shift.
* that logic breaks down a bit with dotted notes, which will have to cross into their neighbour a bit.