I couldn't agree with this more. I used a similar technique on my personal statements, referencing my alternative education background in passing, and my family history (migration and multiethnicity) in connection with my interest and knowledge of the area where I intend to work. So, there were two factors 1) how my past assures my commitment to this field, 2) how my past makes me a strong candidate for this particular program. I think sharing some of my past made my application more unique and personal, but at the same time I placed the most importance on the work I have been doing. As long as you remain professional and not confessional, then you can keep some of your pie, stay dignified, and I think admissions will respect that. I agree you shouldn't "tell all" to get admitted -- make everything clearly relevant.