I am thinking of buying a index smart scale, but why should i?

Convenience of having past values stored and being able to track trends.

I got it mainly so that I did not have to enter my weight into Garmin Connect every day, which I would usually forget to do. This way, when I step on the scale every morning, my weight automatically gets entered into GC.

I was interested in the other measurements on the S2 (body fat, water content, etc.), but I think those are pretty inaccurate (not just on the S2, but on most of these consumer scales). They are probably good for showing trends, but the absolute measurements are not worth much.

Thanks!

so it's basically a scale.

it doesn't improve my other devices or data.

In my head it would make the data more accurate?

Maybe Garmin should try to make some better algorithms using machine learning to try to actually use the data from the scale and other devices to maybe make it more accurate and not be based on a static standard model of some kind.

thinking specifically of kcal burn and other metrics that kinda feels like a "guess". They should have plenty of data to actually be successful in this area. And it would be a major selling point for actually buying a Garmin scale and not some other cheaper alternative.

Yeah, it's a scale. As far as measuring weight goes, it's very accurate, but so is a $20 Walmart scale. As far as all the other stuff goes, it's as good as the other smart scales on the market, which is to say not very good. Measurements like body fat percentage, muscle mass, bone mass, etc. are very difficult to do without really expensive laboratory equipment.

For kCal measurements in Garmin Connect, I think the app does take your weight into account - it certainly should, because weight makes a big difference in kCal burn. But kCal burn is another measurement that is notoriously difficult to do without serious lab equipment. You can estimate it fairly well with a combination of data, but you can't really measure it that way.

Body fat measurements are critical for fitness tracking.  The Garmin Index S2 is wildly incorrect in reporting this metric.  There are many threads that discuss this and so far there is no solution.  So if this is as important to you as it is to me, you may want to look elsewhere.