DT58 1.14inch IP68 Waterproof Smartwatch Bluetooth 4.2, Support Blood Pressure Monitoring / Sleep Mo worth to buy? Thanks for it if those of you who have purchased DT58 1.14inch IP68 Waterproof Smartwatch Bluetooth 4.2, Support Blood Pressure Monitoring / Sleep Mo could share about what you think of the product. I would love any extra info, as it is quite pricey as $38.91 and I just want to know it is good before paying for it.