Here’s some thoughts from my use of a smart watch as a late teen/young adult
I have an “original” apple watch (released in 2015 - end of my senior year of HS), have had it almost since they first came out, and I found it very handy for taking a quick glance at BG while driving or while in class. Freshman year of college I used to wear it into the shower in the dorms to keep an eye on BG and the time before my classes. I don’t wear it much anymore because it runs super slowly, can’t really keep up with the Dexcom app anymore, and yes, I always forget to charge it
Overall I found it handy for making it easier to take a quick glance at how things are going but wouldn’t say it was “critical” to my management in any way. It did spam me with harder to ignore notifications (with haptic feedback on my wrist being harder to ignore than phone vibrations) if I was getting a Dexcom alert though. I sometimes still pull out my watch if I’m going to have a particularly busy day (particularly a busy day in lab, because taking off my gloves to pull out my phone is kinda annoying). But the battery life on the original Apple Watch is very bad, not sure if newer ones are any better and I’m confident other brands are better for this particular aspect.