No phone is waterproof*, the ThinQ is water resistant. There's a big difference. The G7 is rated IP68 - that's being in water up to 4.5 feet deep for up to 30 minutes. The pressure at 4.5 feet is about 2.25 pounds - a lot less than, say putting the phone into the water (which can easily exceed 10 pounds).
As hallux said, it's insurance, not an invitation to go swimming with your phone. If you spill soda on the table, and it runs over and touches the phone, it won't get inside. (Phones used to get destroyed when that happened.) If you use the phone in the rain, it's usually safe (although a drop hitting right on a seam can get in, and there goes the phone).
But don't take the phone into the shower (or even have it in the bathroom while you're taking a shower - the steam can get into the phone and when it cools off it's water - inside the phone). Don't take the phone swimming - even one stroke of your arm, if the phone is strapped to your arm, can exceed IP68 specs.
*Any more, anyway. Motorola used to make a couple of "anything but drive a tank over-proof" phones.