The left and right side differs in more than one way; in the right example you have correctly placed the boolean inside the loop so that it will be read each time. In the left example the initial value will be passed to the loops and that's all. Incorrect data flow.
If you use two while loops then it's often OK to use a local, especially if it's something as simple as a switched boolean (it's therefor often used e.g. to stop multiple loops). In this case the boolean is a switch and there is little chance of a race problem (which you could have if it was latched; then the first loop might have reset the button before the second one has reacted to the initial value change). Could the local be avoided? Well - the second loop could perhaps be avoided, depend on what else you want to do in the loop. With a second loop though you could use an occurence, notifier, functional global etc (a bit of an overkill here though) - there are a number of options. Again - for something simple a local is OK. Often people with experience with textual languages use locals everytime they need the data though; no wiring at all...
