You can use coins to buy power-ups during the games. You can also use them to avoid losing your turn when you wrongly answer a question or avoid falling into the traps on the board in case you have exhausted the free second chance.
On the other hand, you can use coins to spin the Lucky Spin after you run out of free spins, in case you don't want to wait the 30 minutes to spin it again for free.
We invite you to visit the following articles: Power-ups and Lucky Spin to obtain more information about it.