The link for the profile is given there so that people can share their Netflix accounts with people without having to share the passwords. Passwords are a tricky thing if shared can be used to change the password or shared with others. However, a link might be shareable but handleable.
Password should not be shared as every account has limited screens available. If number of users increases then you may find it difficult to watch your favorite show. Because anyone else could be watching it or downloading it.
Let's see how can you use this Feature
Open Netflix Mobile App like this
Open Screen whom you are watching Netflix
Now Home Screen will appear in front of you.
Select "More" option in bottom right corner of page like this
Link of your profile will be written in a box.
Then click on the option "Copy Link".
Link of your profile is copied.
Share it with your friends carefully.