I agree with Peachey.

Phrasal verbs typically sound more informal than their non-phrasal verb equivalents. I think you'll find phrasal verbs are far more common in everyday speech than in, say, an academic journal.

Phrasal verbs are typically the first words children learn growing up, and they often don't learn the more formal, non-phrasal verb equivalents (which are mostly loanwords from Latin or French) until they're older. I think the reason is that phrasal verbs let you be far more expressive with a smaller vocabulary. For example, it's much easier for a kid to learn how to combine four verbs and four prepositions they already know than it is to learn 16 entirely new words. I imagine this was even more true when in the past, when verb conjugation in English was much more complicated and irregular than it is now (like most other Germanic languages).