You couldnt be more correct if you had to be!! I think people dont like the game because of SM's lousy lower tier prizes and the fact that the JP doesnt roll over. But their thinking is flawed. It definitely is all about the odds. You're right too that it has the best odds to win a million anywhere. I know that because I checked the other state's lottery's websites, and you wont find anything with odds as good or better anywhere.
I normally buy the PowerPlay or The Megaplier when I play either PB or MM. (Personally, I think it's nuts not to buy it, but that's just me. I do it because I'm trying to get the first five numbers and win the second prize of either 2 million or 1 million.)
But there is an even smarter way to do it by playing Sweet Million. When I play SM, I make my own "PowerPlay". I play a line of six numbers twice on my ticket(s). I do that because SM isnt pari-mutuel for the first 5 JP winners. (Like The NYS Lottery would ever see 5 JP winners in the same draw. Hell, they cant get 1 JP winner in most draws!) If that line of 6 numbers that I bought twice came in, I'd win 2 million dollars. Doing this is better than buying the PowerPlay in PB because as you correctly pointed out, SM's odds are 1 in 3.8 million. PB's odds are 1 in 5.1 million and the line costs 3 bucks, in SM, it cost 2 bucks. It's better than adding The MegaPlier because although I'd pay 2 bucks per line in MM (same cost as SM) I'd win just 1 million in MM, and the odds in MM to win that million bucks are 100,000 to 1 higher than SM.
I might add that if I had 5 numbers on that SM line I bought twice, the lower tier prize of $500 would become $1,000. 80 bucks for 4 number etc.....