I take it you're not currently checking out adoption for yourself - as my wife and I are.
There are a lot of reasons for overseas adoptions - and "easier" is just simplified code for what it is.
For one thing, cheaper. Domestic adoptions can be outrageously expensive, especially if you want a *baby*. (There are ways around this, but it can be complicated).
But the biggest hassle, in addition to the *time* and commitment, as it can take up to two years to complete - domestic adoptions are 'risky' inasmuch as the whole deal can fall apart - you can go through an agency, go through the home-study, arrange to adopt a baby - and one of the parents or the mother just simply changes their mind - and you went through it all for nothing. Same thing even AFTER YOU'VE ADOPTED - you can LOSE the child you've grown attached to, because the laws favor the biological parents.
With overseas adoptions - this doesn't happen. The child gets here, they're yours - no one's going to give you a call one day and take 'em back.