I can't answer your questions from a clinical perspective, however I'll have a stab at them. I'm a type 1 diabetic, diagnosed when I was 9.
> Do you know why the applicability to type two diabetes is not as clear as for type one?
I'm only stabbing at this, and it's anecdotal, but I believe it is likely due to the lack of consistency across type 2 diabetics. Whilst there is variation in Type 1 Diabetes, it is largely limited to lifestyle but the basic principle is the same - you don't produce insulin yourself. Type 2 diabetes is often caused by insulin resistance, and I guess varies wildly based on the individual, their lifestyle, and their genes.
> I live with someone who has a CGM (continuous glucose monitor) where the device came in a box with an insert saying "do not use this device to make medical treatment decisions." To see any of the readings you have to install an app whose start screen says it's experimental and, again, can't be used to make treatment decisions. But the user's manual has a chapter titled "Treatment Decisions" that tells you how to use it to decide when to take insulin and how much to take. It's frustrating that the messages have to be so contradictory.
I haven't been given a CGM for longer than a few weeks (NHS rules are a bit restrictive in my area if your control is good). However the rationale for not using the CGM to make decisions is based around how it gauges your blood sugar. Because it's relying on blood glucose levels in the skin tissue I have been told that there is a delay, and basically the CGM operates about 15 minutes behind your current glucose levels. This is ok when you're using it to track glucose levels over a day, but not particularly safe if you're relying on it to make a decision for obvious reasons.
> A final question: how essential is it to be tech-savvy to use this technology?
This is a question I have asked myself a few times. As mentioned above, it's pretty difficult to get a pump and CGM on the NHS in my area without proving that you can't treat yourself adequately with regular injections. I am unwilling to sacrifice my health to have a pop at getting a pump, so I had a look at private options. Whilst initially I think there's a fairly steep learning curve, there is quite a lot of documentation provided, and the community is pretty active and helpful. I suppose it's also helped by the fact that there is only a few pumps on the market (relatively speaking). The issue is that if something goes wrong in your config, which is not uncommon for a homebrew solution, then you have to go back to manually adjusting your insulin.