I agree with you 100% - proper clippers and a file do a fabulous job on dogs nails. The only problem is that some dogs absolutely will not tolerate the pressure of the cutting tool on their nails. No conditioning can change it. Shibas are a breed that tend to be particularly senstive to this type of pressure (which is why all of the people in the Shiba groups and many breeders all huge advocates of the dremel). LOL
Many groomers routinely use them. I have also heard of vets recommending them.
Using the dremel (as it is to be used for shortening pet nails) is essentially like filing the nails down from the end. You are simply using the tool to do it for a longer time. The same success could also be achieved by using a file alone, however, I don't know about you, but I do know that my arm strength and patience is not enough to endure manually filing all of my dogs nails to get them to their proper length
The idea is not to file the surface down like a manicure (I was just using the example for the potential of the tool to cause injury) but rather, to "file" the ends, therefore, I don't see the risk of weakening the nails.
I know that the tool keeps spinning even when pressure is not being applied but, without the pressure, my experience is that the dremel simply "bounces" off the surface to which it is applied. No cuts or skin injury (this is not to say that anyone using any tool should not be careful when using it!)
You mention you have a woodworking dremel. This dremel may have faster speeds and thus the potential to do more harm than those made for pet care. The dremel I have is specifically made and marketed for pet care.
In any event, if you don't agree with any of my information or thinking, I won't take any offence! Differences in opinion are what make life interesting!
ps I am glad to hear that Sadie is doing better!