I have a fenix 6 and love it. I use it for everything, but it's too bulky to reasonably go to sleep with. I bought a cheap vivosmart 4 to wear to bed, but when I was messing with the settings, I noticed I have to set it as primary wearable to get it to track sleep. It's listed as "partially compatible" when selecting between it and the fenix. It recommends not using a "partially compatible" device. What can't it do? Is it "bad" to use it as my primary wearable? If so, what's better option? Would the ore modern vivosmart 5 be a better option?