Don't get me wrong, coloratura singing requires a lot skill and technique, and is not for everyone. Some of these pieces require a skilled virtuoso who has had a successful singing career for the past two and half decades at least. But, on the other hand, some of them are actually quite easy, so long as you know what you're doing.
I have found that many coloratura arias are easier to sing than some others that don't have as much vocal decoration. I find it actually a bit tougher to sing arias that have many long sustained notes, because it requires more vibrato and breath support to keep from going flat (I'm looking at you, "Im abendroth"!).
With arias that have more moving notes with long ascending and descending passages, suddenly I have more freedom of movement in my voice. Suddenly I don't need to hold onto a single note for more than two beats. Now I move more freely vocal wise.
Yes, part of it is practice. The other part is just making sure you've got everything in place. And the rest of it whether or not you can keep you breath going.
