Yes, absolutely. I'm quite confident that is the reason. I did it as well. However, if you vote too early, your curation award goes to the author. If you vote too late, you get very little or nothing. I find that most of the time these articles attracting a lot of votes already have a lot of votes on it before the half-hour penalty time is up, so trying to find that sweet spot where your vote actually earns anything significant is a rather daunting task. Too much trouble for me. When I look at my curation rewards they are mostly around the 1-3 thousandths of a cent! I prefer to look at the other side of it and know that when I vote on someone, I am gifting them 2 cents! As the value of Steem rises and my SP goes up, that gift will also go up.