Yes, the use of propanolol in dampening a person's memory is worth it, because the memories the person is trying to forget are often very painful. A person should be able to decide for themselves if they want to erase the painful memory. It is unfair for others to impose on the person whether they should be allowed to erase the memory or not.
Memories are useful information. They can teach us a lot. Instead of erasing the memory the memory's emotional effect should be erased. If they can target the brain to eliminate a specific memory they should be able to eliminate the emotional response to the memory instead, leaving the memory to be accessed and used just as a source of information.
I have bad memories in my past that keep me from doing or thinking stupid things now, without them I'd like to think that'd still be true but I'm not positive and it's not worth the risk for a procedure that sounds extremely dangerous to begin with. I cannot come up with reasons to condone going through with this.