"Traveling is important."
여행 is a noun, by itself, but you need 하는거 for words that are inherently verbs, to make it into a noun.
Example: 행복 = Happiness 행복해 = to be happy 행복하는거 = (the action of) being happy (followed by a description)
걷다 = to walk 걷는거 = (the action of) walking (noun of verb)
저는 행복해 I am happy
행복하는것은 좋아요 Being happy is good
저는 집에 걸어요 I walk home
집에 걷는것을 힘들어요 Walking home is tiring
행복 - happiness, 행복하기 - being happy. You are right but there is a slight difference anyway
The first is polite form, the latter is formal form. Essentially they are/ mean exactly the same thing.
The conjugations (way the verb ends) are different depending on to whom you are speaking. One has more formality than the other. Do you want to guess which one?
The meaning is the same. They're used depending on who you're talking to. 중요해요 is Polite (strangers and people older than you) and 중합니다 is Formal (your boss/teacher)