Playing scratch cards online can be really good, but there are also some advantages of playing off line as well. Some people really enjoy playing a cardboard scratch card because they like the noise and sensation of scratching off the panels. However, some people do not like the mess that they make and the fiddle of having to find a coin to rub it with.
Playing online can cost less money. There are some sites which offer free scratch cards and others which have cheap ones. You do not get this option if you buy them from a shop. There are many more to choose from if you get them online as well. You will find that there are lots of sites that have scratch cards and they will each have a good section of them. This means that if you like a particular type, theme, cost, jackpot, odds or whatever, then you will have a better chance of finding what you want. Having a variety can also make the game more fun, because you will be able to keep trying different types.
Playing online means that you can play at any time. Buying cardboard cards restricts you to only being able to get them when the shops are open. You may have to travel quite a distance to get there as well and that could take you some time. For some people this could be a good thing, as being able to play more often could mean that they will spend more money than they can afford. However, online playing will mean that people who are less able to get to the shops and buy scratch cards can still have a go at playing.
Which way you decide to play very much depends on your own personal taste.