JoeN:
The normal accepted hobbiest way of driving a small LED is to drive it directly from a logic IC pin.
If you just want it to light up an LED then there's nothing wrong with it.
JoeN:
I've heard over and over that this is not the right way to do it
If you've heard that then it's probably because they weren't use a resistor to limit the current properly or something like that.
JoeN:
The Arduino has a reasonably low maximum drive current
It actually has far too much current for normal LEDs (which enter their death zone at 20mA).