1. “Open to life” means not contracepting. Period. It doesn’t have any deeper or more complicated meaning when I use the phrase as opposed to someone else.
2. People who are “open to life” while using NFP to avoid pregnancy will sometimes become pregnant anyway. Depending upon a variety of issues related to fertility, education, temperaments, and circumstances, this is more likely for some couples than for others.
3. The Catholic Church allows the use of NFP but it never does require it.
UPDATED! BONUS! ONE MORE!
4. Financial concerns can absolutely be a legitimate reason for a couple to use NFP to avoid pregnancy.