In my experience (coming from former communist country, now living in US) it's a bit amplified by the fact that these competitions are significantly more popular in those countries than they are for example in US or Western Europe. It just means more in practical terms like getting a good job. I happen to work for the ACM ICPC and if you look at participation (number of contestants) from Western Europe it's much less than countries like China, India or Russia. From what I heard, scoring in such a competition in these countries is really prestigious. Not that it doesn't matter in US or Western Europe, but it's not that important.
