i would, but FB is till the defacto standard to keep in touch with friends/contacts if you aren't living in the same city/country with them anymore.
Additionally, for email, IM, Skype, and text, you need to know their email address, username, or number to contact them. In Facebook, there's a chance that you can find them by just searching their name.
If someone (family or not) does not have my email address and/or phone number there is a reason for it so certainly won't want them contacting me on Facebook...
I know that i wont if id had to write an email, which i dont even have for many of my contacts from these times.