Yes, you can watch in-game ads to boost your mines, and to collect all earnings from a continent, provided you've unlocked the entire region. The boost from advertisements also doubles any other active boosts, making them twice as powerful.

If you have purchased the No Ads Offer from the in-game shop, then you can still boost your mines or collect all earnings, but you do not have to watch the advertisement: you simply tap to claim the benefits instantly.