Self promotion is a tricky thing. In an ideal world, value should be recognized through the process of your work. Unfortunately, the transparency of your work is a multiplier in how people perceive your value.
That's why great coders aren't valued at 10x or 100x that studies say they should be from a productivity standpoint.
Self promotion is a further multiplier on your perceived value. Some people do it enough to counter act the transparency problem and some use it to mask their lack of intrinsic value.
TL,DR:
Perceived value = Intrinsic value * transparency of process * self promotion
That's why great coders aren't valued at 10x or 100x that studies say they should be from a productivity standpoint.
Self promotion is a further multiplier on your perceived value. Some people do it enough to counter act the transparency problem and some use it to mask their lack of intrinsic value.
TL,DR: Perceived value = Intrinsic value * transparency of process * self promotion
So self promotion isn't bad in and of itself.