I have the TG5 - very similar to the TG6 - it's good if light is good, but due to the small sensor not so good in low light. Plus it suffers from flare if there's any backlight because of the protective glass over the lens.
But it's the best of the small sensor tough/waterproof cameras, f2.0 is brighter than most, there's some manual controls plus RAW capability and mine has been reliable despite heavy use in the sea.
I use it mainly as a tough holiday camera - swimming, river rafting, snorkling, sailing. I've played around with it for macros, and was impressed, especially with the focus stacking feature, and I have the flash adapter for macro, but rarely use it as it"s best in bright, natural light. IQ is similar to a top end mobile phone, but not compatable to an aps-c or full frame sensor, but in a brightly lit rock pool it should work well.
I can't find any macro examples, but can take some and upload if you want to see some? There's also a good TG Group on Flickr.
Most my shots are just fun holiday ones in situations where I wouldn't risk using a normal camera.