If you believe the purpose of a life is to thrive and procreate, then it's justified; becoming more attractive and famous will definitely help you find a proper mate, and to pass down your attractive genes to future generations. In that sense, it really doesn't matter if you live to 70 instead of 80, you've already done your job.
Also, I imagine attractive and/or famous people get a lot more opportunities to do exciting things in life, which may make up for the slightly decreased life expectancy. No matter what, you could always end up dying early anyways. It's all about what you want out of life, and what kind of chances you're willing to take.
Being attractive is overrated, and would much rather be smart. The loosing the years part does not really bother me, as life seems long and hard anyways. I would much rather keep those years if those were my choices though. I would rather live a quality life were I impacted the world in some small way, than have all the materialistic things. That is just me though.
The sad thing about toady's society is they believe that you have to be pretty or famous. People have become so focused on the superficial they have forgot what really matters in life. I would never give up ten years of my life for fame. That would mean you lose out on 10 years of love, happiness, of things that are real. Fame isn't real.
Fame and physical attractiveness are egotistical things to wish for, and life is so much more than that, and the process of physically living it is the only way one can really learn what their life is and what they truly want from it. You might lose ten years that you would have realized you didn't want to spend being attractive or famous.
There is no possible to way to justify giving up ten years of your life for a point of vanity! If someone's quality of life is so bad they are willing to give up ten years for attention they should be consulting with professional help. Life is too valuable to give up any of it.
No, it is not worth losing those ten years just so you can become more attractive, or become famous. For me those ten years of life are worth a lot more than any of these things, and the longer you are alive the more that you can go and do.