If you want a smart watch that uses cellular data without using up the battery, consider upgrading to the Samsung Gear S3. A close cousin to the Gear Sport, the S3 has all the perks of an LTE smart device (downloading apps, texting, checking email) and, unlike the Apple Series 3, it won’t quit after three hours. In fact, you could feasibly get 72 hours out of this LTE version of the Samsung Gear Sport.
For all of you outdoorsmen, Casio returned to IFA this year with its latest Pro Trek watch. The Casio WSD-F30 takes the same great features of previous generations and slaps them inside of a slightly slimmer body. The 60.5mm × 53.8mm × 14.9mm body is still pretty huge, but it’s considerably smaller than what came before it and still maintains 5ATM water resistance, MIL-STD-810, and even low-temperature resistance.
Unfortunately, you won't be able to respond to alerts (like messages and emails) from the Charge 3. That's a feature sequestered to smartwatches, but you can see most of the content of an alert on the device's screen. Considering how narrow the device's screen is, reading through a long email won't be the most comfortable experience. But at least that message will be glanceable on your wrist, as will news headlines, text messages, and other alerts as well.