The biggest mistake is that you have to order the extended warranty at the same time with the device

The warranty extension has one major drawback.
You have to order the device to be insured at the same time.
If you send the unit but within the trial period back, one must also "return" the insurance.
So you do not change your mind when ordering the device.
Actually, it should be possible to reorder the guarantee with no time pressure even within 4 weeks.
If you know that you want to keep the device.
Finally, the insurance also begins yes only after usually 2 years, after the regular warranty.
So you would have had time to read through the conditions of insurance for now.
But who can under time pressure when buying the warranty must make the same time as the purchase of the device?