There is a subtle difference between the two. Some drones are designed to withstand underwater water pressure, and some can only tolerate rainfall or a drizzle. There is a difference. You have to get all these definitions sorted out before doing anything. Waterproof drones are able to fully submerge into the water. The electronic components of such drones are sealed in double-closure chambers. So, there is no way water can enter the device and spoil it. However, coming to water-repellant and water-resistant drones, they are not sealed properly. There are chances that water will enter the parts of such drones. However, they can only handle mild snow, drizzle, or rain at the most. If you happen to submerge them, they will get spoilt. So, now it is much more clear than before.