The wording here seems, to me, to have some silly limitations. For example, there are apps I have thought would make a nice gift for a friend before, and the easiest way to do this is to buy an unlock key and send it to them.
But, with these rules, I guess the goal is that I have to send them a gift card instead? I'll just not bother and get them something else.
Though you could make the argument that it would be more complex than it's worth. There's regional issues, like can I redeem your gift code from cdkeys.ru in the US. Can I return the app afterward if I don't want it for a 160 rubles credit? They might already need to handle that stuff for gift cards though.
But, with these rules, I guess the goal is that I have to send them a gift card instead? I'll just not bother and get them something else.