Highly overrated, unless you are looking at specific positions. Salaries vary little in entry level positions based on where you got your degree. Your ability to demand a higher salary or gain promotions will only be impacted by your ability to perform the tasks required by the position, and those skills are demonstrated as you move up the ranks, not based on where you went to school.
This is the same kind of fable that travel team coaches spin to parents of 10 year olds, ‘if you don’t do this, you won’t have a chance’. We’ve hired 200 people this year, pay on the higher end of the market, and our talent is from schools large and small, directional colleges and name universities. Our upper management is recruited based on prior experience and success, not on where they got their degree.