If you are used to playing the national lottery scratch cards, then you will be aware that a percentage of what they make is donated to charity. This is for their lottery, scratch cards and online games as well. This means that playing with them will mean that you are donating to good causes.
Other scratch cards do not give to good causes, unless they specifically state that they do. This means that if you want to give to a good cause when you are playing scratch cards, then you need to be careful about which company you choose. You may not want to give to a good cause and this may mean that the prize fund is bigger with the company that you choose and you have a better chance of winning. This may not always be the case though.
You may feel that it is not right to play a scratch card without giving to charity because this is what you are used to doing. However, there is nothing to stop you giving some money directly to a charity and then buying a scratch card that does not give. This means that you will directly benefit a charity that you feel strongly about. You can also give more if you wish.
Some people seem to justify the expense of buying a scratch card because they are giving to charity. Only a small percentage of what you spend goes to a charity and so it is better for you to give half the money you would have spent to a charity and save the rest. You would end up giving more to the charity and not spending so much overall. Of course, you may enjoy playing and if this is the case, then do so, if you can afford it but be honest with yourself as to why you are playing.