I think for some New Yorkers the habit of buying $1 Powerball without Powerplay per line is inherited from buying $1 Mega Millions per line. Until now, New York Lottery still does not offer multiplier for Mega Millions (Megaplier) in New York. Therefore, some people who are used to playing Mega Millions may think that Powerball works the same, and just don't have the habit to pay $1 more for Powerplay. As some of you said, they may not have noticed that if you play Powerplay and you win 5 white balls without red ball, you always get X5 for that particular prize and get $1M rather than $400,000 to $1M depending on the multiplier chosen if this policy does not exist.
It can be reflected from the fact that Powerplay option ($2 per line) is chosen for only less than 10% of sales. For example, in the Powerball drawing for Nov 6, where $123m jackpot was won in Michigan, there was $3,285,518 Powerball sales, in which only 6% ($196,649) of sales was with Powerplay option. In other drawings, the ratio of Powerplay:Total Powerball sales is consistently lower than 10% in New York State. While in North Carolina, where both Powerplay and Megaplier has been offered for both games, the sales of Powerplay is higher when it is compared to Total Powerball sales, the figure is consistenly over 25%.
Just google The Lotto Report to see more about sales of PB and MM. It is a website from a Texas man in which you can even see whether states are having a loss or a gain in a total sense for a particular drawing for Powerplay or Megaplier.
From a micro psychology view, maybe it is easier for $1 tickets to be sold because it is cheaper. When you are buying $10 Powerball without Powerplay, there are 10 lines. However, if you use $10 to buy Powerball with Powerplay, there are only 5 lines.
Anyway, Powerplay does not increase the probability of winning the jackpot, nor the jackpot prize size. This is partly compensated by automatically multipying 5 times for second tier prizes. However, I would definitely choose Sweet Million to play if I want to win $1 million becasue I am using $1 to win a million with odds of 1 in 3,838,380, better than using $2 to win the same amount in Powerball with odds of 1:5,138,133. If you just used $1, you would lose $800,000 in Powerball if you really won.