Amazfit Band 5 Fitness Tracker with Alexa Built-In, 15-Day Battery Life, Blood Oxygen, Heart Rate, S worth to buy? Thanks for it if those of you who have purchased Amazfit Band 5 Fitness Tracker with Alexa Built-In, 15-Day Battery Life, Blood Oxygen, Heart Rate, S could share about what you think of the product. I would love any extra info, as it is quite pricey as $39.99 and I just want to know it is good before paying for it.