It's about controlling blood glucose, yes. If your keeping your insulin levels in normal physiologic ranges then counting calories is unnecessary - the body will self regulate through hunger, and excretion.

total carbohydrates, fiber, added sugars, protein, and electrolytes, all of which are extremely useful on a keto diet.

If your doing keto, sure you can keep track of those things if you want to, but it isn't necessary. It just complicates things, I've found better adherence with friends by giving them a CGM, since its passive and ways running.