I think that both methods are useful and that they are a part of the package of intervention tools. Some people prefer medication, others prefer psychotherapy. In some cases, both are used together.
Regarding propranolol, this is an experimental treatment that my team is currently testing, and we are getting very interesting results. This kind of drug therapy aims at reviving the traumatic memories, and, as the brain encodes them again, at alleviating their emotional impact.
We are not trying to erase people's memories, but simply to reduce their emotional impact, because we believe that in cases of post-traumatic stress disorder, the problem is caused by the overly intense emotional impact of memories.