eMatrix has become a treatment of choice for darker skin types because it radically reduces the incidence of post inflammatory hyperpigmentation that occurs more frequently with laser.
Because darker skins are prone to this post treatment pigmentation, often a physician will reduce the energy settings to avoid this potential problem. In which case you end up needing more treatments to achieve smoothing. But, you don't end up trading scars for dark spots.
Time is your friend. Collagen development occurs over time - so you may not see obvious benefit for months.
The sequential series of treatments minimizes downtime and prompts multiple "collagen-inducing" events. You're building new collagen with each treatment and after a number of treatments your skin will have enough new layers of collagen to provide some level of smoothing. (5 or 6 sessions is not uncommon for acne scarring)
Severe scarring can require even more sessions and ice pick scars usually need some kind of surgical management.
Light skins can tolerate laser better than dark skins and energy settings can be high, so in that instance, laser is better. But to prevent unwanted pigmentation, the non-laser like eMatrix is a good choice.
It IS hard to wait to see improvements and I wish there were a magic system that could repair all that old acne damage without so much effort. But technologies are improving all the time and we have better options than ever before.
Be patient - take excellent care of your skin while in treatment - always use sunblock.