I owned a Sony band before with my Xperia z2 and it did really and amazing job of being waterproof, comfortable in the wrist and providing call and notification vibration alerts. But to be honest that is it of its features.
These days there are many fitness bands it the market that provides the heart rate, running time, steps taken, stairs climbed etc at a much cheaper price and are as effective as this one and even more
Most things you can do with this device is get notified for alerts and calls and not much more. Its just a expensive Sony branding with no display and no additional features .
Its just only makes sense when you buy it with your Xperia device otherwise its just an costly Sony accessory nothing more . I have used it and not much I could use it for also not having a display on it at 6000 rupees is also a deal breaker and also you don’t get what you are paying so much for, I think its not a device you want as there are better options available at much cheaper pricea.