A good committed relationship also involves friendship and benefits.
That all depends on what the other person wants. Often, people who are in a FWB relationship .. It's because they don't want commitment. Problems often occur when one person changes the "rules" and wants more.
Yes
Yes.
Generally speaking, in terms of propagating the human race, sexual activity is ordered toward commitment in order to provide protection and assistance while the mother is carrying the child and while the offspring grow.
But that is a potential problem with "friends with benefits"---that feeling and sense of commitment may fuel a commitment that has no real basis in intellectual reality and it may not last beyond the point of pregnancy and infancy in today's world.
Sure, it is possible, but from what I have observed, not likely.