uncoated/coated wire questions

2 part question. first, why would uncoated jumper wire ever really be needed? is there an advantage to using it short distances over the coated version? the other question is, in the process of soldering, is there a risk of burning off the enamel of coated wire too far along the length of it, such that you risk shorting components?
for anyone wondering, I got an answer by posting in a different thread. From 2informaticos:
"You need to insist a bit with the solder iron, to burn the enamel on the solder point; not easy to burn it accidentally too far.
Do not damage the enamel with the cutter/knife, pay attention on that."