It's the more rasperry pi "thing" because it's simpler, cheaper and more accessible. You don't want to use a barrel jack because it's too easy to plug in the an

It's the more rasperry pi "thing" because it's simpler, cheaper and more accessible. You don't want to use a barrel jack because it's too easy to plug in the an adapter with the wrong voltage or polarity and it's not as ubiquitous as USB power supplies.