You bring up some interesting points, and a lot of people probably wonder the same thing when faced with making a big life change. It's all very scary at first because the future is unknown. Carrying on with the status quo seems safe because at least, it's known.
Here are some of my thoughts...
I think it's important to take whatever plan you are following initially on faith. The authors have more experience with their own plans than any of us will ever have.
That said, what do you want to get out of changing your way of eating? Losing weight is only one part. There is also being freed from addictive behaviour in your relationship to food. Sweets are highly addictive, both physically and mentally. If you have ever turned to them for comfort, or called yourself "and emotional eater", you know what I mean.
Right now, you probably can't imagine life without dessert. You may think that you'll be an "outsider" when it comes to social occasions because your way of eating will be so different from everyone else's.
The way you will learn to eat with the SP will become the way you eat. It's the process that is all important. Do SP as written at first, always listening to your thoughts and how your body feels. If you feel safe after a while to venture out, do it, but again listen to your thoughts and body. Does branching out cause you to crave? Do you think about and anticipate sweets?
You are the "someone" that gives yourself the alternative. Just because it exists and other people are doing it, doesn't mean that it's right for you.
Trust me when I say that you can live quite comfortably without them. It does take a while, and it's not easy but it can be done.
From my own experience, I know I should avoid them and most of the time I do. My physical cravings are gone. When I choose to eat them, I know the consequences they carry because I have listened and learned.
There is one thing in your post that I'm not sure of.
Is weight loss at the expense of our health an option?
I think if weight loss is achieved by starvation diets, diet pills, or any quick fix method, the answer is yes.
Do you think that you are healthy now? Not thin, not fine, but truly healthy in body mind and spirit?
How do you see your health suffering by following the Schwazbein Principle?