is there any reason to use lower settings?
It's been a few years but I used to solder professionally (I worked on electronics production line for a short time): Too high a heat has a few risks:
1 - you can melt the material under the copper and have the copper pad lift off the board. A real bummer as it can be near impossible to repair the board if pads are small and close together.
2 - on through-hole parts like connectors the plastic may melt making the insertion of the mating parts tough
3 - this one is a little tenuous and I have no proof, but I have been cautioned that any use of a soldering iron on chip capacitors risks cracking the ceramic (due to rapid temp change) that will lead to reliability issues down the road. Chip caps (being surface mount) are intended for soldering in the reflow oven which is much more gentle than a soldering iron from a thermal shock point of view. By extension, a hotter soldering iron would increase the thermal shock.
4 - as others said, you'll trash the tip faster
