Hi Linda,
Just recently, I, had the good fortune to find a passport for two family members. YES, keep, or scan (the whole thing) and keep them. I feel they can really help "flesh out" the life of that ancestor, and anything more than names & dates is a bonus, in my book. In my case, the passport has also been helpful in cracking open a brick wall in my research. I can only hope to find more passports.
Leah Heilpern Snider