When the energy works be together with the massage, we can give a emotional touch in the massage, and give a little touch of energy to the client "battery" :o)
For the regular, I use both together in my massage therapies.
I think the biggest benefit to the client of combining energy with massage is having a unique tool to address causative factors that massage therapy alone cannot reach alone. Giving clients an alternative to pulverizing a muscle into submission comes in close second. ;)
Approaching massage from either one specific way, to me is wrong. I do not try to control either. When this is done, my massage is "flat". Afterwards, it feels like something was missing and both my client and I sense it.
"Allowing" a massage to evolve is so much better. To your question: Without either, there is a "lacking". Benefits differ, because of all the varibles.
Now there is a discussion... varibles. Temperature, gender of therapist, gender of client, age of therapist, age of client, physical apperance of both, first vibe from both, music likes/dislikes, table, linen, lighting, breath of each and on and on..... This is why therapists need to always consider the client's comfort and consider it a priviledge to massage and not a job.