I had T2D, well controlled now, my A1C is below the diabetic diagnostic range.
I used CGMs, and they taught me a lot about how my body reacted to food and exercise.
But I sweat a lot and they would always fall off, halving the useful life of each monitor. I would probably still use them from time to time if they didn't sweat off; and if an implantable version was available for a reasonable price (under $500, with no ongoing costs), I'd probably get it.
I feel like a lot of prediabetic people could learn a lot about their situation with this. I think this is a very good thing.