wonder why this option ( is this a gift?) is available when purchasing the bundle??

Exactly for this reason -- if you select "it is a gift", then you purchase a giftable link for the whole bundle (including all games), which you are allowed to give to somebody. If you do not select "it is a gift", then you purchase the game licenses for yourself, and the organizers do not allow you to give any of the keys to other people (mostly because you can still access the Desura keys or the DRM-free versions yourself, which would make this a case of piracy.)

See this: http://www.indieroyale.com/faq#nosharing -- "Sharing Steam keys because you already own a game in the bundle is not allowed. The same applies for Desura keys. If your friend wants a bundle you should gift them or they can purchase it themselves."