Less voltage more amp? switch characteristis
...Because the power passing the switch is the same?


You are misunderstanding what the rating means.  If you see "24V 0.5A" on a switch, it does not mean that the switch will drop 24V when 0.5A pass through it.

There is a component that will do that:  It's called a 48 Ohm resistor, and it will dissipate 12 Watts of power under those circumstances.

An ideal switch will dissipate no power.  The rating "24V 0.5A" actually is two ratings:  "24V" means,  when the switch is open, it can safely withstand 24V, and no current will flow, and it will dissipate no power.

"0.5A" means, when the switch is closed, it can safely carry 0.5A.  Ideally, the voltage across the switch will be 0V in that case, and the switch will dissipate no power.  In reality, there will be a very small voltage across the switch, and it will dissipate a small amount of power.  "0.5A" means that as long as the current is less than 1/2 an amp, the power dissipated will not be enough to harm the switch or anything else.

The two ratings combined have one other meaning.  When you open the switch contacts, there usually will be a spark.  The spark is hot, and it potentially can damage the switch.  I know a lot less about how arcs form and how they are extinguished, but the combined "24V 0.5A" rating means that the arc will not last long enough to do any harm if the current was 1/2 an amp or less when you started to open the switch, AND the voltage can rise to no more than 24V by the time the current finally stops and the arc goes out.