It all depends on where you think this will go. If you want to just stick to doing video, the GoPro is a really good option. If you have any desire to get into photography … then the TG7 is the way to go.
I have been doing u/w still photography on and off since circa 1995. I know what I am doing most of the time. I am a fairly experience u/w still photographer. I consider myself an "advanced-intermediate" photographer. I have won two u/w photography medals, bronze and silver, recently. Not an international expert but have the basics covered.