[IvanVergiliev]

Your second assumption is only valid for people who conflate the two disciplines. If you don't recognize that competitive programming and software engineers have completely different goals and requirements, then being trained in competitive programming may very well lead you to bad programming practices - e.g. single-letter names are usually fine for competitions, while at the same time usually horrible for engineering.

However, if you recognize the differences and use the skills you learn in the two as complementary, you can be better at both.