The battery is the single reason why I got the Amazfit. I use as a dumb health tracker and occasional GPS running. It easily lasts 4 weeks on a single charge. That's one less proprietary charging cable to bring on a trip.
What's the deal with Amazfit? I have an Amazfit GTR and it's been rock solid for a couple of years. Before that, I had an Amazfit Bip for a few years which was incredible. It did notification, GPS, heart rate tracking, always on display and battery life of 2 - 4 weeks. It did this years and years ago, when the best Android could do was 24 - 48 hours, and it did it for like £60 instead of £200. It still works too!
The Bip in particular seemed so ahead of what the average person expected from a smartwatch due to state of Android and Apple offerings at the time.
I don't know about Amazfit, but I have a Garmin that also lasts weeks. There are some differences: WearOS/WatchOS watches essentially use a more power-efficient/less powerful version of a smartphone-class SoC. They have to because they run a full Linux/XNU kernel and a pretty complete userland. Watches with weeks-long battery life typically use something that is more akin to a powerful microcontroller with operating systems tailored to such low-end hardware.
Besides that some watches (like several Garmin models) use transflective displays. They do not have to actively emit light during daytime (in contrast to OLED), sunlight is reflected. In contrast, OLED displays have to be more bright in sunlight to be visible.
This is what I'd assumed. But then I also assumed that's actually an exceptionally expensive and high resource approach to take compared to using higher level smartphone chips. By using lower level hardware, they're having to do more bespoke hardware design, and more bespoke low-level firmware and software creation, and also support all of that extra creation. This seems like the super expensive, heavy, slow way of building a smartwatch.
So I guess the "what's the deal" what's trying to understand how some random knockoff looking company ("Amazfit" in 2016) took the super expensive, heavy, slow way of building a smartwatch, and got better results than some of the largest most notorious software/hardware companies on the planet.
Ultimately, they took the pebble approach, and pebble also got a huge amount of backing and extra funding, time, support etc. and seemed to commercially fail. But Amazfit is still going strong.
There is an implied question there, but you may want to get a bit more specific. The deal seems to be that you get a really good fitness watch for a fraction of the cost of Android and Apple offerings, if your statement and my first review of their website is accurate.
Fair point, I elaborated a bit here: https://news.ycombinator.com/item?id=44854032
You're right in your assessment. My "what's the deal" was more asking "how did such a small unknown-to-me company do this with similar or better results to the worlds largest hardware/software companies (Apple/Google) in 2015/2016?" It sounds like they did it with even more specific and low level hardware and software, which makes it even more impressive.
Like I said, my bip did GPS, bluetooth notifications, hardrate tracking and most of the other things an iWatch did, but it had 20x the battery life and cost 1/5 of the price. I find this an unbelievable achievement that I don't understand, and it's rarely talked about.