Well, sometimes people start out like this. I once answered an email from somebody whose Dhamma group had degenerated a little - this was in a Buddhist country - and the teacher had allowed himself to give out some numbers of the lottery to somebody and they won the jackpot. So then instead of the Dhamma group being interested in his Dhamma talks they became more interested in getting numbers for the lottery. Obviously this was an unbeneficial result.
With the intention to donate a lot of it to good causes, only if the intention is followed through. Many times good intentions can easily degenerate into materialism. We may have the intention in the beginning to donate a large amount of money to other things but then we get hooked on the idea of easy Kamma. One person was wondering why their Kamma wasn't as good as the other person's Kamma who won the lottery. I pointed out that actually if they started to believe that they could get things so easily, they may not put in enough effort to make good Kamma along the way.
I'm not going to say good or bad because it's a personal choice, but I do know that a lot of people have a hard time with this gambling idea. They think they can control it and then it gets out of control. In Australia they have a lot of charities that run lotteries. It's a shame that they have to have lotteries to encourage people to give to a worthy cause. It would be nice if the charities could be able to raise enough by people just giving the money without wanting anything in return. But unfortunately that is what many charities have to do in order to raise the money necessary for the work they want to carry out. Many people can become addicted to gambling. On the other hand I've also heard about an elderly couple in Sydney who won a lottery and set up a soup kitchen for people. So they made a lot of good Kamma with it, as fortunately their good intention followed through with their winning.