That's really not technically correct. If the load is shorted the fuse will momentarily see the voltage according to a voltage divider, including the internal resistance of the source and remaining resistance of the wiring and short. It's the current, of course, that will blow the fuse.
You are wrong. The fuse blows when there is 10+ amps through it. The fuse resistance is low maybe a drop of only 0.1V or so under normal operation and by the time it blows maybe a drop of 1V. So 12V circuit or 24V circuit doesn't matter the voltage drop across the fuse at rated load is tiny. Fuses have Voltage and breaking current ratings, so at high enough voltages and currents the fuse won't work.
