It does say this fairly clearly - although the author is correct in that by determining the outcome on the server side means that even if the game isn't completed, you can still be credited for the win.
There is even an option to bypass scratch card play and get the prize immediately (Reveal Instant Wins outcome automatically.)
There isn't really much skill involved offline (compared to none online). That being said, I wonder how many people don't spot winning prizes when they buy a ticket in the store - if I find a ticket, I might check!
That part is almost certainly to comply with gambling licencing laws. There are different laws if it's a game of chance or luck. That's why many raffles (a game of chance) have a really simple question at the end, to turn it into a game of skill, legally.