It would be great to get them as gift while mining for Island Parts instead of coins. I think no one needs the extra coins. Only low level player would need them but they don't have access to the mine. I'm on level 162 and have more than enough.

Or what about changing gifts for daily log in? Today a Marble Key, tomorrow some food and maybe some coins on another day?

Or as prize in Spinning Wheel, in Bingo, in Events?